Registration of uterine contractile activity during labor. Methods for registering uterine contractile activity

Date: 03.03.2020

The modern approach to the management of childbirth in various types of obstetric pathology, the use of highly effective SDM stimulants, antispasmodics and analgesics require widespread use of objective methods for registering SDM.
The proposed classification of SDM is based on data on the duration and partographic features of labor, qualitative features of SDM and the state of the cervix during labor, and on the nature of labor.
Normal labor activity:
a) with normal SDM, with an increase in the amplitude-time indicators of contractions, an increase in the number of a normal uterine cycle, a mature cervix;
b) in the absence of a peco-coordinated SDM and an increase in the normal uterine cycle, in the presence of certain signs of an insufficiently "mature" cervix.
Weakness of labor:
a) with hyperdynamic SDM;
b) in case of a sub-standard SDM.
Excessive labor:
a) with hyperdynamic SDM;
b) with moderately severe hyperdynamic or normodynamic
SDM.
The methods for registering SDM during pregnancy and childbirth are divided into the following groups:
external tocography;
internal tocography (contact);
^ lectrohysterography ^ lectroscography);
rheohysterography (rheotocography);
cervicodilactometry - determination of the degree of cervical dilatation during childbirth;
radiotelemetry of intrauterine pressure (radiotelemetry internal tocography).
External tocography makes it possible to obtain information
about the coordination of uterine contractions. For a comprehensive assessment of SDM, special methods of graphical analysis of current-grams have been developed. For hysterographic studies, a three-channel hysterograph is used. Having three highly sensitive strain gauges, the device allows you to obtain high-quality graphic

where the numerator represents the product of the amplitude of each contraction (p) by its duration (i), calculated in 10 minutes, and the denominator T is the time of the analyzed process.
Using this formula allows you to get an idea of the quantitative work of various parts of the uterus.
The positive aspects of external hysterography include asepticity and safety of studies. However, the value of the indicators for this method is influenced by the thickness of the subcutaneous adipose tissue, the tension of the muscles of the anterior abdominal wall, the shape and rotation of the uterus during contractions, the degree of pressing and the correct position of the sensors, the quality of the recording depends on the damper properties of which.
It is known that as one approaches childbirth, the characteristic of pregnancy high-amplitude Brexton Hicks contractions turn into labor contractions (Strukov V.N., Mepis L. S, 1973]. in the area of the uterine body Physiological childbirth proceeds with the presence of a “triple descending gradient”: contraction occurs in the area of the uterine fundus and, decreasing in intensity and duration, passes to the body and the lower segment.
In the study of the external tocograms during normally proceeding childbirth, the variability of the amplitude-time characteristics of contractile activity was established. When the cervix is cut from 4 to 9 cm, the intensity of contractions ranges from 25 to 55 mm Hg. Art., frequency - from 4 to 10 for 10 minutes, duration of contractions - from 50 to 120 s.
The analysis of tocograms is carried out in combination with clinical data and the dynamics of the opening of the uterine pharynx (uterine opening). The quantitative assessment of histerograms is based on the analysis of the vertical and horizontal parameters of contractions on the contraction sinusoid, the calculation of various ratios and indices of the SDM.
To assess the uterine contraction, the most widespread was the Montevideo unit, which is determined by multiplying the amplitude of uterine contraction by the number of contractions in 10 minutes. However, Montevideo units do not reflect such a parameter as the duration of single contractions or their phases. Therefore, it was proposed to multiply the value of Montevideo units by the duration of uterine contractions. Use ^ -ty units if necessary.
Currently, in obstetric practice, the asymmetry coefficient is used in the analysis of hysterograms. The importance of calculating that coefficient is that it reflects the power of uterine contractions: the lower the value of the coefficient, the more active the power of contractions.
P od internal tokografney understand the intrauterine method of registration of SDM. There are different methods of internal tocography: intra-amnial, ^ extra-amnial, intervillous and intramyometrical by transabdominal puncture of the uterus and introduction of micro balloons into the corresponding areas.
02 ml. The most important difference between the methods of internal tocography from other methods of examining SDM is the possibility of accurate quantitative measurement of intrauterine pressure.
Electrogensterography allows you to register the electrical biopotentials of the uterus and is carried out from the surface of the abdominal wall, the surface of the uterus or directly from the thickness of the myometrium. Includes two main graphical features. The first is the variable component of bioelectric activity, which begins before the onset of target contraction with an amplitude of 100-1000 μV and an oscillation frequency of 0.5-2 or more per second. The second is a constant component from the anterior abdominal wall. The controversy in the interpretation of certain features and the need for a careful assessment of the results do not diminish the value of this method in assessing SDM, especially in combination with other research methods.
The reohysterografin method is based on the registration of fluctuations in the resistance of the tissues of the uterus located between the electrodes, to which an alternating current of a high frequency is supplied. Fixation of ^ lec- trodes is performed on the anterior abdominal wall in the places where the corners of the uterus are projected or above the pubis and on the sacrum. When analyzing rheohysterograms, the rhythm and symmetry of waves, graphic features of the ascending and descending parts, the nature of the “peak”, and the features of additional waves are taken into account. Mathematically calculate the duration of the entire wave as a whole and its individual components - the ascending part, the top and the descending part, the amplitude of the amplitude in relation to the calibration level. The high sensitivity of rheography makes it possible, regardless of the thickness of the abdominal wall, to judge the contractile activity of the lower segment of the uterus, which is important for the diagnosis of SDM pathology and prognosis of labor.
Cervicodellactometry allows you to register the degree of cervical dilatation. The technique consists in attaching piezoelectric crystals with the help of special clamps to the cervix and recording based on the change in the time of signal passage between two piezo crystals.
The method of radio telemetry with the help of the "Capsule" system allows registering temperature, pH and pressure in various parts of a woman's genitals. The Kap-Sula radio telemetry system includes a receiving-analyzing and recording device designed to receive radio signals emitted by radio capsules, radio pills or ndoradiosondes. To determine the pressure in the cavity, there is a special modification of the radio capsule sensor, which provides measurements in the range of 0-200 mm Hg. Art., for pH in the vagina in the range of 1-9.0 and continuous measurement of temperature from 34-42 ° C. Changes in the physiological parameters of the uterus are recorded on the moving tape of the recorder. Registration of intrauterine pressure with a whole fetal bubble is carried out by introducing a capsule into the uterine cavity above the belt of contact of the presenting part with the entrance to the malium pelvis, extraamnially, with drained waters - intraamnially.
_When analyzing intrauterine pressure during normal labor, it is necessary to register 5 parameters of contractions: uterine tone, contraction intensity (maximum intrauterine pressure in kilopascals), intensity of contractions of voluntary muscles during attempts, duration of contractions and duration of intervals between contractions.
The tone of the uterus during normal pregnancy is 3-8 mm Hg. Art., by 36 weeks of pregnancy, it hangs, amounting to 10 - 12 mm Hg. Art.
In a normal labor act during the period of opening, the contractions become more frequent and more intense, by the end of the first period the frequency of contractions is 4-4.2 per 10 minutes, the intensity is 50 - 55 mm Hg. Art., uterine activity 200 - 240 IU, uterine tone 7-9 mm Hg. Art.
During the period of exile, the frequency and intensity of contractions, the activity of the uterus, increase. Normally, the average frequency of contractions during pushing is 5 to 10 minutes, the average intensity is 55-60 mm Hg. Art., the activity of the uterus 280 - 300 IU, the tone of the uterus hangs up to 11 - 13 mm Hg. Art.
Obtained hysterograms are processed using quantitative and qualitative indicators. A significant drawback is the subjectivism of the doctor in assessing the indicators characterizing SDM, and the delayed time of their analysis. The use of computer analysis of histerograms makes it possible to obtain a decoding of the indicators in real time, which makes it possible to timely correct the arisen violations. During childbirth, continuous monitoring of the nature of the SDM over a long period and the prompt analysis of hysterograms is possible only with the use of the WM, which allows one to obtain accurate quantitative characteristics of the SDM, to monitor the dynamics of their changes.
Partographic analysis of SDM indices using computed tocography revealed that there is a significant relationship between the total duration of labor in primiparous and multiparous, and in all phases of labor. Thus, the rate of cervical dilatation in primiparous women was 0.984 cm / h, and in repatriates, 1.686 cm / h. Moreover, the rate of cervical dilatation is most pronounced in multiparous, especially when the cervix is 8-10 cm wide. In multiparous, there is a slight slowdown in the rate of cervical dilatation from 5 to 8 cm, nevertheless, the rate remains quite high. The number of contractions during the opening of the cervix changes insignificantly in both primiparous and multiparous, and only when the cervix of the uterus is opened 8-10 cm, the number of contractions is significantly greater in primiparous, which is obviously associated with a lower location near - the bruising part in multiparous.
Computer analysis of histerograms with the use of the algorithm for analyzing SDM indicators makes it possible to analyze the amplitude-time parameters in real time, which significantly increases the diagnostic value of the method.

Signs of the body's biological readiness for childbirth

The physiological course of childbirth is possible only in the presence of a formed generic dominant. The formation of a generic dominant can be judged on the basis of changes in the bioelectric activity of the brain in pregnant women and women in labor. In normal childbirth, the entire cerebral cortex is involved in the dominant process with the emergence of a large number of interhemispheric connections. Of great importance for the onset of labor and its correct regulation against the background of the general preparation of the woman's body for childbirth is the readiness of the cervix and the lower segment, as well as the sensitivity of the myometrium to the effects of contractile substances. An important role in the development of labor is played by the fetus, its pituitary-adrenal system. The readiness of a woman's body for childbirth is determined by a number of signs, the appearance of which indicates the possibility of a spontaneous onset of labor in the near future, or allows one to count on a positive effect from the use of labor stimulants. The state of readiness for childbirth is most clearly manifested by the changes found in the female reproductive system, especially in the uterus. To diagnose changes that occur during the formation of a woman's body readiness for childbirth, the following tests are most common: determination of the "maturity" of the cervix, oxytocin test, non-stress test, mammary test, test based on measuring the value of the resistance of the cervix to electric current, cytological examination vaginal smears, etc.

Modern methods of registration of uterine contractile activity

External hysterography (pneumatic, hydraulic, mechanical and photoelectric devices with sensors of mechanical activity).

Internal hysterography (radio telemetry, balloonometry with sensors for recording intrauterine pressure).

Electrohysterography (indirect and direct).

In this case, the following indicators are assessed:

1. The tone of the uterus is normally 8-10 mm Hg. and increases with the development of the generic process, in the II period it increases 2 times in comparison with the I, in the III it decreases to the initial level.

2. The intensity of contractions - increases with the development of childbirth and normally in the first period ranges from 30 to 50 mm Hg, in the second - it decreases, but taking into account the attachment of contractions of the striated muscles (attempts), reaches 90-100 mmHg. Immediately after the birth of the fetus, the volume of the uterus decreases and the force of its contractions increases sharply: intrauterine pressure rises to 70-80 mm Hg, intramyometrical pressure to 250-300, which contributes to the separation of the placenta.

3. The duration of contractions as labor progresses increases: in the first period from 60 to 100 seconds, in the second - it is equal to 90 seconds.

4. The interval between contractions in the process of development of the labor act decreases from 10-15 minutes at the beginning of labor, to 60 seconds at the end of the first period, in the second period - about 40 seconds. Normally, 3-5 contractions occur in 10 minutes.

5. Uterine activity - is determined on the basis of a comprehensive mathematical assessment of the duration of contractions, their intensity and frequency over a certain period of time (usually 10 minutes). The most widespread is the assessment in units of Montevideo (EM). Normally, the activity of the uterus increases with the progression of labor and fluctuates between 150-300 IU.

Normal contraction of the uterus during labor is a "triple downward gradient", with the wave spreading from top to bottom with decreasing strength and duration.

During physiological childbirth, the dominant of the bottom is noted, which is explained by the thickness of the myometrium and the accumulation of the contractile protein actomyosin. Generic activity is most effective with a bottom dominant, less effective with a body dominant, and ineffective with a lower segment dominant.

B. Methods for determining the condition of the fetus. Cardiotocography - 1 ... analysis of cardiac activity: registration of changes in the intervals between individual cycles, simultaneous contraction of the uterus and fetal movement, the leading method for assessing the condition of the fetus in the antenatal period. During pregnancy - indirect CTG - determination of the basal rhythm (average value for 10 minutes). Types of BR variability - monotonic with low amplitude; slightly undulating; undulate; saltatory. CTG assessment system: N - 8-10 points, initial signs of fetal ID impairment - 5-7; serious violations - below 4; 2 .evaluation of fetal reactivity (change in cardiac activity in response to functional tests): non-stress test (CVS response in response to its movements), oxytocin test (stress) - in response to uterine contraction; nipple stimulation, sound stimulation, atropine test.

Indirect cardiography: after 32 weeks, electrodes to the anterior abdominal wall of the pregnant woman with a simultaneous ECG of the mother (differential of maternal complexes). Direct CG: directly from the fetal head during childbirth when the CM is opened from 3 cm - determination of the heart rate, the nature of the rhythm, the size and duration of the ventricular complex and its shape (N-120-160 per minute).

Phonocardiogram - microphone at the point of the best listening to heart sounds. PCG + ECG - calculation of the duration of the phases of the cardiac cycle.

Echography (ultrasound) - dynamic observation of the fetus; establishment of pregnancy and assessment of its development in the early stages; assessment of the vital activity of the embryo (sor-tones, physical activity); the state of the placenta (localization, thickness, structure).

Fetal biophysical profile - an assessment of the functional state of the fetus. Parameters: fetal respiratory movements, physical activity, fetal tone, amniotic fluid volume, maturity of the placenta. Evaluation criteria: N - 12-8 points; doubtful condition of the fetus and the possibility of complications - 7-6; severe intrauterine hypoxia and a high risk of complications.

Doppler blood flow of the mother-placenta-fetus system - information content, non-invasiveness, safety throughout pregnancy. A qualitative analysis of the curves of the current flow rates (siastolic ratio, pulsation index, resistance index) is an assessment of the severity of fetal hemodynamic disturbances. Doppler echocardiography - diagnostics of congenital malformations of the SC. Color Doppler mapping - diagnostics of vascular pathology (retroplacental blood flow, vascular disorders of the placenta, cord entanglement, malformations of the cervix) - early diagnosis of obstetric complications with the formation of placental insufficiency.

Ultrasound determination of the amount of amniotic fluid: oligohydramnios, polyhydramnios according to the amniotic fluid index. Amnioscopy - transcervical examination of the lower pole of the fetal bladder (chronic hypoxia, prolongation, isoserological incompatibility of the blood of the mother and the child.

Amniocentesis - obtaining amniotic fluid for B / C, hormonal, immunological, cytological, and genetic research (fetal condition, degree of maturity).

Diagnosis of abnormalities of labor can be carried out by analyzing clinical symptoms or by graphically depicting the opening of the uterine pharynx during labor in the form of partograms. Another way to improve the diagnosis of labor is to study the contractile activity of the uterus by objective methods: external and internal hysterography. At one time, external hysterographs with pneumatic sensors became widespread, however, hysterographs with the use of strain gauges are more advanced, since they are easier to use, inertialess.

Internal hysterography method based on the registration of intrauterine pressure (AMD). Back in 1870, the domestic scientist N.F. Tolochinov proposed a manometer mounted in a cylindrical vaginal mirror. The manometer was brought to the fetal bladder and measured the value of the intrauterine pressure.

The transcervical method of recording intrauterine pressure using a polyethylene catheter was proposed by Williams, Stallworthy (1982). It has become widespread both in our country and abroad.

One of the options for internal hysterography is the method of radiotelemetry, the essence of which is that a miniature radio station is introduced into the uterine cavity, which registers intrauterine pressure, converting it into radio waves recorded in the form of curves on a special apparatus.

The apparatus and method of two-channel internal hysterography has been developed. Registration of intrauterine pressure through two channels became possible due to the discovery of a previously unknown dependence of self-regulation of the uterus during childbirth. During contractions, a zone of increased intrauterine pressure is formed in the region of the lower segment of the uterus due to the emergence of a functional hydrodynamic cavity, limited by the lower segment of the uterus, the head and shoulder of the fetus.

It is of interest to study the contractile activity of the uterus (UDM) using the simultaneous registration of intrauterine pressure and external hysterography. Uterine contractions begin earlier than intrauterine pressure builds up. Moreover, in the first stage of labor, the increase in intrauterine pressure occurs later than the contraction of all parts of the uterus, on average by 9.4 ± 1.5 s.

A comparative analysis of the methods of external and internal hysterography showed that the latter has a number of advantages, since it allows registering the basal (main) tone of the uterus, which is especially important in the diagnosis of hypo- and hyperdynamic types of uterine contractile activity.

The main difficulty in diagnosing violations of the contractile activity of the uterus is to determine the most informative indicators. A lot of researchers recommend analyzing the contractile activity of the uterus by 15-20 parameters. However, the analysis of these indicators requires a lot of time and the use of computers.

In order to quantify the contractile activity of the uterus according to the data of external and internal hysterography, some researchers have proposed various methods: mathematical analysis of hysterograms, assessment of the effectiveness of labor by impulse pressure, i.e., the product of the average pressure value and the time of its action, Montevideo units, Alexandria unit, active planimetric unit, etc.

Multichannel external hysterography. For a more detailed study of the contractile activity of the uterus during labor, multichannel external hysterography is used. A five-channel hysterography was used with the location of the sensors in the area of the fundus and body of the uterus on the right and left to the lower segment of the uterus along the midline. Later, an electronic hysterograph with a mechanophotoelectronic converter was developed. In recent years, a dynamo-uterograph - DU-3 three-channel with ink recording has been designed. The device uses modern strain gauges. The device is reliable and portable.

Analysis of hysterograms:

the external hysterogram is more indicative of the dynamics of the volume of the uterus and its membrane at the location of the sensor than the magnitude of the tension of the uterine membrane;
in the uterus during labor, 3 hydrodynamic systems can be clearly distinguished:
- cavity and lining of the body of the uterus;
- cavity and shell of the lower segment;
- the cavity of the vascular depot of the uterus, which affect the amplitude of the external and internal hysterograms;
a pathological labor contraction differs from a physiological one not so much in the absolute value of the tension of the myometrium during its contraction, but in the violation of the order of change in the volumes of various parts of the uterus, which leads to a violation of the mechanism for converting the energy of the isometric tension of the myometrium into external work to change the tissues of the cervix;
since the external and internal hysterograms have a fundamentally different physical nature, the use of the same methods of analysis and interpretation is incorrect in relation to the basic physical laws operating in the uterus contracting during childbirth.

Despite the presence of contradictory data on the contractile activity of the uterus, further study of the qualitative and quantitative characteristics of the contractile activity of the uterus will help to identify such informative indicators of its disorders that can be used for its diagnosis.

2. Modern methods of registration of contractile activity

For an objective assessment of the contractile activity of the uterus during pregnancy, to determine the onset of labor, to identify abnormalities of labor during the labor act and to assess the effectiveness of their treatment, to record the contractile activity of the uterus in the successive and early postpartum periods, a large number of methods for their objective registration have been proposed, which can be conditionally divided for external and internal hysterography (tocography).

Multi-channel external hysterography has become widespread in our country, which allows us to have information about the contractile activity of the uterus in its various parts, both in normal conditions and in pathology. The method is simple, non-invasive and makes it possible to judge the place and beginning of the wave of contraction, the direction and speed of its propagation, the coordination of contractions of various parts of the uterus, allows you to record the duration, size, nature of contractions and the interval between them. The disadvantage of external hysterography is that the readings of the devices are influenced by the thickness of the subcutaneous fat layer, skin tension, displacement of the uterus and its rotation during contractions, the place of attachment of the placenta, limited behavior of the woman in labor, insufficient information content in the subsequent period.

Internal hysterography (tocography). With internal tocography (the sensor is located in the uterine cavity), intrauterine pressure is recorded outside and during the contraction, which indirectly, but quite accurately, allows one to judge the features of the contractile activity of the uterus. Methods of internal tocography compare favorably with methods of external hysterography, since they can be used to obtain reliable data during and outside contractions in certain units of measurement (mm Hg). Among the methods of internal tocography, radio telemetry is very promising.

3. Etiology and classification of abnormalities of labor

The causes and factors that determine and contribute to the development of SDM disorders, it is advisable to distinguish by the time of their development (occurrence) before the onset of pregnancy, during it and during childbirth. Such factors before pregnancy include the following: extragenital diseases of a somatic and infectious nature, neuroendocrine pathology and diseases of the genital organs, aggravated indicators of reproductive function (stillbirth, bleeding during childbirth, miscarriages, etc.), biological and constitutional (age under 18 and after 30 years old, body length 150 cm or less, narrow pelvis), occupational hazards, everyday difficulties and bad habits. The number of causes and factors increases during pregnancy: toxicosis and other types of pregnancy pathologies, anomalies in the development of the fetus and placenta, incorrect insertion of the head and position of the fetus, breech presentation, premature rupture of amniotic fluid, polyhydramnios and multiple pregnancy, large and giant fetuses. Finally, in the process of childbirth, causes may arise that lead to a violation or aggravation of the existing pathology of SDM: a long preliminary period, the onset of labor with insufficient "maturity" of the cervix, pathology of the placenta, incorrect and unjustified use of pharmacological agents and other interventions.

The basis of the pathogenesis of SDM disorders is discorrelation between the higher parts of the central nervous system and subcortical structures, endocrine glands and the uterus, which often occurs with insufficient biological readiness for childbirth, disorders of steroidogenesis and prostaglandinogenesis, with pathological morphological changes in the uterus, with various disorders of the neuroendocrine system.

Classification.

I. Pathological preliminary period.

II. Weakness of labor:

1. primary;

2. secondary;

3.weakness of attempts: primary, secondary

III. Excessive labor (overactive uterus).

IV. Discoordinated labor activity:

1.discoordination;

2. hypertonicity of the lower segment of the uterus (reversible gradient);

3.convulsive contractions (tetany of the uterus);

4. circular dystonia (contraction ring).

4. Pathological preliminary period

The pathological preliminary period is a kind of protective reaction of the pregnant woman's body to the development of regular labor in the absence of readiness for childbirth and, above all, of the uterus. The protective reaction of the pregnant woman's body is manifested in the form of discoordinated contractile activity of the uterus and is aimed at the maturation of the cervix and its opening.

Clinic of the pathological preliminary period:

1) cramping pains in the lower abdomen, sacrum and lower back, irregular in frequency, duration and intensity, lasting more than 6 hours;

2) the woman's sleep and wakefulness is disturbed, she is tired, exhausted;

3) during external examination: the tone of the uterus is increased, especially in the lower segment, parts of the fetus are poorly palpated;

4) vaginal examination: increased tone of the pelvic floor muscles, narrowing of the vagina, the cervix "immature". Despite prolonged cramping pains, there are no structural changes in the cervix and it does not open.

The duration of the pathological preliminary period is from 6 hours to 24–48 hours. With a long preliminary period, the psychoemotional status of the pregnant woman is disturbed, fatigue sets in and signs of intrauterine fetal hypoxia are observed.

Diagnostics is based on:

1) anamnesis;

2) external obstetric examination;

3) vaginal examination;

4) hysterographic data (contractions of various strengths and durations are recorded at unequal intervals);

5) cytological examination of the vaginal smear (cytotype I or II is detected, which indicates insufficient estrogen saturation).

Treatment is indicated for full-term pregnancy with a preliminary period of more than 6 hours. The choice of the method of treatment depends on the psychoemotional status of the pregnant woman, the degree of fatigue, the state of the birth canal and the state of the fetus.

1.With the duration of the preliminary period up to 6 hours, the presence of a "mature" cervix and a head fixed at the entrance to the small pelvis, regardless of the state of the integrity of the fetal bladder, treatment should be started with electroanalgesia or acupuncture session. Sometimes therapeutic electroanalgesia is recommended, i.e. 1.0 ml is injected before the session. 2% solution of promedol, or 2.0 ml. 2.5% pipolfen solution, or 1.0 ml. 1% solution of diphenhydramine intramuscularly. In parallel, estrogenic hormones are administered (estradiol dipropionate 0.1% - 30,000 units or folliculin 20,000 units).

2. With the duration of the preliminary period up to 6 hours and an insufficiently "mature" cervix, seduxen or relanium 10 mg intramuscularly or intravenously is recommended, slowly by 20 ml. saline solution. At the same time - treatment aimed at the ripening of the cervix: estrogens, antispasmodics.

3. With a prolonged preliminary period (10-12 hours), when irregular pain persists after the administration of seduxen, 10 mg must be re-administered. seduxen + 2.0 ml. 2% solution of promedol + 2.0 ml. 2.5% pipolphene solution; 30 minutes later, sodium oxybutyrate (GHB) is administered in the form of 20% solution of 20-30 ml (at the rate of 60-65 mg per 1 kg of a woman's weight) intravenously together with 20 ml. 40% glucose solution.

4. If the duration of the preliminary period is more than 12 hours and severe fatigue, the woman should be immediately provided with medication-induced sleep-rest (GHB in combination with promedol, seduxen and pipolfen), as well as 0.5 mg of atropine). Sometimes (in order to relieve painful discoordinated contractions), treatment in the pathological preliminary period begins with the use of Partusisten 10 ml. (1 amp.) + 250 ml. physical solution, intravenous drip for 2-3 hours. If within 1 day it is not possible to relieve painful contractions in a woman, to improve the condition of the birth canal, then for women with a full-term pregnancy, "immature" cervix, OAGA, large fetus, breech presentation, anomalies in the development of genital organs, extragenital pathology, and in pregnant women over 30 years old - operative delivery by cesarean section is indicated. Caesarean section is necessarily indicated when signs of intrauterine fetal hypoxia appear against the background of a long preliminary period.

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Subject table of contents "Registration of uterine contractile activity. Hysterography. Cardiotocography (CTG).":
1. Registration of uterine contractile activity. External hysterography. Multichannel external hysterography. Hasin's formula.
2. Internal hysterography (tocography). Registration (measurement) of intrauterine pressure. Units of Montevideo.
3. Radio telemetry. Cardiotocographs.
4. Intranatal cardiotocography. Indications for intrapartum cardiotocography (CTG).
5. Evaluation of data of cardiotocography (CTG). Basal rhythm. Normal basal rhythm. Basal rate. Fetal heart rate variability.
6. Oscillations. Normal oscillation amplitude. Undulating curve type. Oscillation variability.
7. Acceleration. Sportive, periodic acceleration. Deceleration. Sportive, periodic deceleration.
8. Classification of decelerations. Early, late and variable decelerations.
9. Atypical variable deceleration. Deceleration amplitude. Assessment of uterine activity.
10. Decoding of cardiotocography (CTG). Clinical evaluation of cardiotocography data (CTG). Saltatory rhythm of fetal heart contractions.
11. Sinusoidal rhythm of fetal heart contractions. Krebs scale. Krebs estimate. Krebs points. Zaling's test.
12. Algorithm of labor management in violation of fetal cardiac activity.

Registration of uterine contractile activity. External hysterography. Multichannel external hysterography. Hasin's formula.

For an objective assessment of the contractile activity of the uterus during pregnancy, to determine the onset of labor, to identify abnormalities of labor in the process of labor and to assess the effectiveness of their treatment, recording contractile activity of the uterus in the successive and early postpartum periods, a large number of registration methods have been proposed, which can be conditionally divided into external and internal hysterography (tocography).

External hysterography. For the first time external hysterography by using Mare capsules I, fixed to the anterior abdominal wall, was used by M. Schaffer in 1896. Later, pneumatic sensors were used by S.М. Becker (1938), I.I. Yakovlev (1961), M. Ya. Martinshin (1961), but this method was abandoned due to its technical imperfection. Then they began to use more advanced electromechanical, induction, photometric [Vishnevsky A.A. 1962] sensors.

The most advanced were strain gauges [GA Shminke, 1969; Iersianinov L.S. et al., 1969; Khasin A.Z., Kondratyev GL., 1969; Reynolds S.R. et al., 1954; Okatomi T., 1970, etc.].

All modern cardiotocographs equipped with sensitive strain gauges.

We have received widespread use multichannel external hysterography, which allows you to receive information about the contractile activity of the uterus in its various parts, both in norm and in pathology. The method is simple, non-invasive and makes it possible to judge the place and beginning of the contraction wave, the direction and speed of its propagation, coordinated reductions different parts of the uterus, allows you to record the duration, size, nature of contractions and the interval between them.

To assess the effectiveness of labor, A.Z. Khasin proposed a formula:

where E is the efficiency of labor, P is the pressure determined by the amplitude of the wave according to the calibration signal, g / cm2; d - duration of the fight, s; t - time equal to 10 minutes.

With the help of a crocorrelation line, which is drawn from the point of the beginning of the wave of contraction in the area of the fundus of the uterus, vertically downward from the right, it is possible to determine the difference t (in seconds) in the time of occurrence of the wave of contraction in other parts of the uterus in relation to the beginning of the wave in the area of the fundus on the right. You can calculate the correlation dependence effectiveness of reductions different parts of the uterus from the effectiveness of reducing its fundus.

The disadvantage of external hysterography is that the readings of the devices are influenced by the thickness of the subcutaneous fat layer, skin tension, displacement of the uterus and its rotation during contractions, the place of attachment of the placenta, limited behavior of the woman in labor, insufficient information content in the subsequent period.

External hysterography (pneumatic, hydraulic, mechanical and photoelectric devices with sensors of mechanical activity).

Internal hysterography (radio telemetry, balloonometry with sensors for recording intrauterine pressure).

Electrohysterography (indirect and direct).

In this case, the following indicators are assessed:

3. The duration of contractions as labor progresses increases: in the first period from 60 to 100 seconds, in the second - it is equal to 90 seconds.

Normal contraction of the uterus during labor is a "triple downward gradient", with the wave spreading from top to bottom with decreasing strength and duration.

Phonocardiogram - microphone at the point of the best listening to heart sounds. PCG + ECG - calculation of the duration of the phases of the cardiac cycle.

Amniocentesis - obtaining amniotic fluid for B / C, hormonal, immunological, cytological, and genetic research (fetal condition, degree of maturity).

Childbirth is called a complex biological process, which results in the expulsion of the ovum from the uterus through the natural birth canal after the fetus reaches maturity. Physiological childbirth come on the 280th day of pregnancy, starting from the first day of the last menstruation.

Childbirth- This is a reflex act that occurs due to the interaction of all systems of the body of the mother and the fetus. are still insufficiently studied. Therefore, the search and accumulation of factual material on the study of the causes of the onset of labor continues to this day.

First of all, childbirth arise in the presence of a formed generic dominant ... Nervous centers and executive organs take part in its formation. It is like the first wave of a conductor's baton, which the entire orchestra is waiting for, after which all instruments begin to sound harmoniously and harmoniously. The "instruments" of this complex "orchestra" are: nerve centers and executive organs, sex hormones that affect various formations of the central and peripheral nervous system, uterine receptors that perceive irritations from the ovum. Even 1-1.5 weeks before the onset of labor, the electrical activity of the brain increases significantly.

The fertilized egg irritates the receptors of the uterus, which, through a complex system of hormonal, nervous and humoral factors, causes an increase in the tone of the uterus. The uterus begins to contract. Intrauterine pressure and fetal size also affect the contractile function of the uterus. Some hormones (oxytocin, for example) accumulate throughout pregnancy, so that at a certain point, having reached the right amount, they can take part in starting the process of childbirth. Although it should be said that all hormones of the body take part in this process to a greater or lesser extent.

The onset of childbirth is preceded by the harbingers of childbirth and the preliminary period.

Harbingers of childbirth - These are symptoms that occur one month or two weeks before delivery. These include: displacement of the center of gravity of the pregnant woman's body anteriorly, the shoulders and head are retracted ("proud step"), the lowering of the fundus of the uterus due to the pressing of the presenting part of the fetus to the entrance to the small pelvis (in primiparous this occurs a month before childbirth), a decrease in the volume of amniotic fluid waters; discharge of the "mucous" plug from the cervical canal; no weight gain for the last two weeks or a decrease in body weight up to 800 g; an increase in the tone of the uterus or the appearance of irregular cramping sensations in the lower abdomen, etc.

Preliminary period lasts no more than 6-8 hours (up to 12 hours). It occurs just before childbirth and is expressed in irregular painless contractions of the uterus, which gradually turn into regular contractions. The preparatory period corresponds to the time of the formation of the generic dominant in the cerebral cortex and is accompanied by biological "ripening" of the cervix. The cervix softens, takes a central position along the wired axis of the pelvis and is sharply shortened. A pacemaker is formed in the uterus. Its function is performed by a group of cells of the nerve ganglia, which is most often located closer to the right tubal corner of the uterus.

Regular contractions testify to the beginning of childbirth. From the onset of labor to the end of labor, a pregnant woman is called a parturient woman, and after childbirth, a parturient woman. The generic act consists of the interaction of the expelling forces (contractions, attempts), the birth canal and the object of childbirth - the fetus. The process of childbirth occurs mainly due to the contractile activity of the uterus - contractions.

Contractions- these are involuntary rhythmic contractions of the uterus. In the future, simultaneously with the involuntary contractions of the uterus, rhythmic (voluntary) contractions of the abdominal press occur - attempts.

Contractions characterized by duration, frequency, strength and soreness. At the beginning of labor, the contraction lasts 5-10 seconds, reaching 60 seconds or more by the end of labor. The pauses between contractions at the beginning of labor are 15-20 minutes, by the end their interval is gradually reduced to 2-3 minutes. The tone and force of contraction of the uterus is determined by palpation: the hand is placed on the fundus of the uterus and the time from the beginning of one contraction to the beginning of the other is determined by the stopwatch.

Modern methods of registration of labor activity (hysterograph, monitor) make it possible to obtain more accurate information about the intensity of uterine contractions.

The interval from the beginning of one bout to the beginning of another is called uterine cycle... There are 3 phases of its development: the beginning and growth of uterine contraction; maximum tone of the myometrium; relaxation of muscle tension. The methods of external and internal hysterography in uncomplicated childbirth made it possible to establish the physiological parameters of uterine contractions. Contracting activity of the uterus characterized by features - a triple descending gradient and a dominant of the fundus. Contraction of the uterus begins in the area of one of the tubal corners, where the "pacemaker" is laid (the pacemaker of the muscle activity of the myometrium in the form of ganglia of the autonomic nervous system) and from there gradually spreads down to the lower segment of the uterus (first gradient); this decreases the strength and duration of contraction (second and third gradients). The strongest and most prolonged contractions of the uterus are observed in the fundus of the uterus (fundus dominant).

The second is reciprocity, i.e. the relationship of contractions of the uterine body and its lower parts: contraction of the uterine body helps to stretch the lower segment and increase the degree of cervical dilatation. Under physiological conditions, the right and left halves of the uterus contract simultaneously and in a coordinated manner during a contraction - the coordination of contractions horizontally. The triple descending gradient, the dominant of the fundus and reciprocity are called the vertical coordination of contractions.

During each contractions in the muscular wall of the uterus, contraction of each muscle fiber and each muscle layer occurs simultaneously - contraction, and the displacement of muscle fibers and layers in relation to each other - retraction. During a pause, contraction is completely eliminated, and retraction is partially. As a result of contraction and retraction of the myometrium, the muscles are displaced from the isthmus into the body of the uterus (distraction - stretching) and the formation and thinning of the lower segment of the uterus, smoothing of the cervix, opening of the cervical canal, tight fitting of the ovum with the walls of the uterus and expulsion of the ovum.

In uncomplicated childbirth, all mechanisms work clearly and harmoniously, the result of their work is the onset of childbirth and the birth itself.

The transcervical method of recording intrauterine pressure using a polyethylene catheter was proposed by Williams, Stallworthy (1982). It has become widespread both in our country and abroad.

Analysis of hysterograms:

the external hysterogram is more indicative of the dynamics of the volume of the uterus and its membrane at the location of the sensor than the magnitude of the tension of the uterine membrane;
in the uterus during labor, 3 hydrodynamic systems can be clearly distinguished:
- cavity and lining of the body of the uterus;
- cavity and shell of the lower segment;
- the cavity of the vascular depot of the uterus, which affect the amplitude of the external and internal hysterograms;
a pathological labor contraction differs from a physiological one not so much in the absolute value of the tension of the myometrium during its contraction, but in the violation of the order of change in the volumes of various parts of the uterus, which leads to a violation of the mechanism for converting the energy of the isometric tension of the myometrium into external work to change the tissues of the cervix;
since the external and internal hysterograms have a fundamentally different physical nature, the use of the same methods of analysis and interpretation is incorrect in relation to the basic physical laws operating in the uterus contracting during childbirth.

WITH abusive the activity of the uterus during childbirth is characterized by tone, intensity (strength) of the contraction, its duration, the interval between contractions, and rhythm.

To assess the contractile activity of the uterus during childbirth, use the usual palpation control and objective registration of uterine contractions using special equipment.

With palpation control with a hand located in the upper uterus, the duration, strength and frequency of contractions are assessed. To get an idea of the coordination of contractions of the right and left halves of the uterus, it is necessary to palpate these parts of the uterus simultaneously with both hands. Palpation of the fundus, body and lower segment of the uterus makes it possible to determine more intense and prolonged contractions of the fundus and body of the uterus in comparison with the lower segment.

Among the objective methods for registering the contractile activity of the uterus, methods of external and internal hysterography (tocography) are distinguished.

External hysterography(tocography) can be performed using sensors for recording mechanical activity (pneumatic, hydraulic, mechanical and photoelectric devices) and using electrical sensors (indirect electrohysterography from the anterior abdominal wall, rheohysterography). These methods are aseptic and safe. However, the indicators of external hysterography are influenced by the thickness of the subcutaneous fat, the tension of the muscles of the anterior abdominal wall, and the correct placement of the sensors.

Internal hysterography(tocography) is carried out using pressure recording sensors (radio telemetry, balloonometry, measurement of pressure in the vessels of the umbilical cord during the third stage of labor, etc.), using electrical sensors. To monitor the dynamics of the dilatation of the cervix, you can monitor using cervicodilatometry.

Internal hysterography is performed transcervically and transabdominal. With internal hysterography, more accurate data are obtained on the total pressure in the uterine cavity, on the basis of which the tone of the uterus and the nature of the contractions are judged. However, when using these methods, there is a danger of infection and opening of the fetal bladder. With external and internal hysterography, the woman in labor should be in a forced position.

The method of radio telemetry has a number of advantages over other methods, since the registration of contractions occurs at a distance by means of radio communication, which ensures the freedom of behavior of the woman in labor. A miniature radio station is inserted into the uterine cavity through the cervical canal (extraamnially - with the whole waters, intraamnially - with the poured out) (Fig. 53).

In practical obstetrics, the most widespread method is external hysterography due to the ease of use and sufficient accuracy of the result. Internal radio telemetry, which is more often used for scientific purposes, also has its adherents.

To assess the uterine activity, the most widespread were the Montevideo units (EM) proposed by N. Alvares and R. Caldeyro-Barcia (1952). IU is determined by multiplying the force of contractions of the uterus (in mm Hg) by the number of contractions in 10 minutes.

Contractile activity of the uterus (SDM) in labor is characterized by the following main indicators: tone, strength (intensity) of contractions, its duration, interval between contractions, rhythm and frequency of contractions and the presence of attempts in the II stage of labor.

Intrauterine pressure changes during labor: 6-8 mm Hg. Art. - in the I stage of childbirth; 20-25 mm Hg. Art. - in the II period; in the third period, the tone of the uterus decreases sharply and is almost equal to the tone of the uterus at the beginning of the first stage of labor.

Uterine activity increases as labor progresses from 120-150 to 200-250 IU.

The contraction at the beginning of the first period with the normal course of the labor act lasts 60-90 s, at the end of the first period 100-120 s, and during the expulsion period about 90 s. It should not be forgotten that the duration of the contraction, determined by palpation, is about half as long as with instrumental measurement, because palpation is a less sensitive method. The interval between contractions is gradually decreasing and is about 60 seconds in the first stage of labor, 35-40 seconds at the end of the second period.

Rice. 53. Schematic representation of the radiotelemetric registration method

intrauterine pressure (a) and a graphical representation of the relationship between

clinical data and results of recording intrauterine pressure (b)

The force of contractions increases in the first stage of labor from 30 to 50 mm Hg. Art. In the II stage of labor, the force of contractions decreases slightly, but due to the addition of attempts, it reaches 90-100 mm Hg. Art.
To assess the contractile activity of the uterus, the asymmetry coefficient is used. Its decrease is accompanied by an increase in the power of uterine contractions. This coefficient is determined in two ways: 1) the ratio of the duration of the contraction phase to the duration of the relaxation phase; 2) the ratio of the duration of the contraction phase to the duration of the contraction. The asymmetry coefficient in the first stage of labor is 0.4-0.45, and in the second period - 0.35.
The study of the contractile activity of the uterus in the III period showed that the uterus continues to contract rhythmically, but the frequency of contractions is lower than in

II stage of labor, and their intensity is much greater. In the subsequent period, according to radiotelemetry data, there are 3 phases: Phase I begins after the birth of the fetus and continues until the first clinical and radiotelemetric signs of placental separation appear; Phase II begins with the appearance of the first signs of separation of the placenta and continues until its complete separation from the walls of the uterus;

Phase III - from complete separation of the placenta to the birth of the placenta. The tone of the uterus before the separation of the placenta is almost equal to the tone of the uterus in the first stage of labor, and after the separation of the placenta it almost doubles. The intensity of contractions in the III stage of labor is much higher than in the I and II periods. The radiotelemetry method makes it possible to predict the amount of blood loss in the subsequent and early postpartum periods. With an increase in the tone of the uterus in the subsequent period, blood loss will be minimal, with a decrease in tone, blood loss increases sharply. The main parameters of the contractile activity of the uterus are presented in table. ten.

Table 10

The main parameters of the contractile activity of the uterus in different periods of physiological childbirth

External hysterography (pneumatic, hydraulic, mechanical and photoelectric devices with sensors of mechanical activity).

Internal hysterography (radio telemetry, balloonometry with sensors for recording intrauterine pressure).

Electrohysterography (indirect and direct).

In this case, the following indicators are assessed:

3. The duration of contractions as labor progresses increases: in the first period from 60 to 100 seconds, in the second - it is equal to 90 seconds.

Normal contraction of the uterus during labor is a "triple downward gradient", with the wave spreading from top to bottom with decreasing strength and duration.

Phonocardiogram - microphone at the point of the best listening to heart sounds. PCG + ECG - calculation of the duration of the phases of the cardiac cycle.

Amniocentesis - obtaining amniotic fluid for B / C, hormonal, immunological, cytological, and genetic research (fetal condition, degree of maturity).

Women in labor usually arrive at the maternity hospital during the period of disclosure. Each of them has on hand an exchange card, which contains all the information about her health and the results of the examination during the entire pregnancy. Upon admission to the maternity hospital, a woman in labor passes through a sanitary inspection room, where, after measuring body temperature and blood pressure (BP), the passport part of the birth history is filled in. Next, the patient undergoes sanitization (shaving hair on the perineum, enema, shower). After that, putting on sterile underwear and a dressing gown, she goes to the prenatal ward. With a whole fetal bladder, not very strong contractions, or with the head of the fetus fixed to the entrance to the pelvis, the woman in labor is allowed to stand and walk. It is better to lie on your side, which prevents the development of "compression syndrome of the inferior genital vein." To speed up labor, a woman in labor is recommended to lie on the side where the nape of the fetus is determined.

During childbirth, the patient is not fed, since at any time the question of the provision of anesthesia may arise (intravenous anesthesia, intubation, artificial ventilation). Caring for a woman in labor in the first stage of labor consists in washing the external genitalia every 6 hours and, in addition, after the act of defecation and before vaginal examination. For this purpose, a 0.5% solution of potassium permanganate in boiled water is used. The woman in labor must have an individual vessel, which is thoroughly disinfected after each use.

During the period of cervical dilatation, it is necessary to carefully monitor the general condition of the woman in labor, the nature of labor, the state of the uterus, the opening of the cervix, and the advancement of the head.

Control over the general condition of the woman in labor. When assessing the condition of a woman in labor, they find out her state of health (the degree of pain, the presence of dizziness, headache, visual disturbances, etc.), listen to the heart sounds of the woman in labor, systematically examine the pulse and measure blood pressure. It is also necessary to monitor urination and rectal emptying. Overflow of the bladder and rectum prevents the normal course of the period of opening and expulsion, the discharge of the placenta. Overflow of the bladder can occur due to its atony and lack of urge to urinate, as well as in connection with the pressing of the urethra to the pubic joint by the head of the fetus. In order to avoid this, the woman in labor is offered to urinate on her own every 2-3 hours; if spontaneous urination is impossible, then they resort to catheterization. During the period of cervical dilatation, anesthesia is performed.

Assessment of uterine contractility. In the clinical assessment of labor, attention should be paid to uterine contractility. It is characterized by the tone of the uterus, the interval between contractions, rhythm, frequency. On palpation, it is difficult to judge the intensity of contractions and the tone of the uterus. The tension of the uterus during contraction during a contraction is determined by the doctor's palpation sensations only some time after the onset of the contraction, and the woman in labor begins to feel the contraction even later. With palpation of the duration of contractions, their true duration turns out to be shorter, and the size of the intervals between them is increased. It is possible to more objectively judge the contractile activity of the uterus using hysterography, rheography or radiotelemetry.

Multi-channel external hysterography allows you to obtain information about the contractile activity of the uterus in its different parts.

For a more accurate quantitative measurement of the force of contraction of the uterus, internal hysterography (that is, gr af and u) is used - the determination of the pressure in the uterine cavity using special sensors inserted into it. Intrauterine pressure indirectly, but quite accurately, allows one to assess both the intensity (or strength) of the uterine contraction during contractions, and the degree of relaxation of the uterine muscles between contractions.

With all types of registration of the contractile activity of the uterus in the first and second periods, waves of a certain amplitude and duration are recorded on the curve, corresponding to the contractions of the uterus.

The tone of the uterus, determined by hysterography, increases with the development of the labor process and is normally 8-12 mm Hg.

The intensity of labor increases as labor progresses. Normally, in the first period it ranges from 30 to 50 mm Hg. The duration of contractions in the first stage of labor increases from 60 to 100 s as they progress.

The interval between contractions decreases as labor progresses, amounting to 60 s. Normally, 4-4.5 contractions occur in 10 minutes.

To assess uterine activity, many methods have been proposed based on a comprehensive mathematical assessment of the duration of contractions, their intensity and frequency over a certain period of time (usually 10 minutes). The most widespread is the assessment of uterine activity in Montevideo units (EM). Montevideo units are the product of the contraction intensity by the frequency of uterine contractions in 10 minutes. Normally, uterine activity increases with the progression of labor and amounts to 150-300 IU. To assess the contractile activity of the uterus, the Alexandrian units are also used (the value of the Montevideo unit, multiplied by the duration of the contraction).

To assess the contractile activity of the uterus, you can use computer technology, which makes it possible to obtain constant information about the contractile activity of the uterus, taking into account many of its parameters. In this case, it is possible to judge the deviations in the nature of labor and carry out the appropriate correction under the control of a computer.

To assess the course of the generic process, E. Friedman (1955) proposed to carry out a partograph (partus - childbirth), i.e. a graphical representation of the course of labor based on the rate of dilatation of the cervix. This also takes into account the advancement of the presenting part of the fetus (head, pelvic end) along the birth canal.

Maintaining a partogram or intensive observation map allows you to determine whether labor is proceeding correctly or not (Fig. 5.20). In this case, it is necessary to take into account whether this is the first childbirth or repeated. The rise of the partograph curve indicates the efficiency of labor: the steeper the rise, the more effective the labor is. The rate of cervical dilatation depends on the contractility of the myometrium, cervical resistance and their combination.

The condition of the uterus and the fetus in it can be determined with an external obstetric examination. It is performed systematically and repeatedly, records in the history of childbirth should be made at least every 4 hours. The round ligaments of the uterus during physiological childbirth are strained evenly on both sides. The contraction ring during physiological childbirth is defined as a weakly expressed transverse groove. By the height of the contraction ring standing above the pubic articulation, one can roughly judge the degree of cervical dilatation (Schatz-Unterberger sign). As the cervix opens, the contraction ring moves higher and higher above the pubic joint: when the ring is 2 fingers above the pubic joint, the pharynx is 4 cm open, when standing on 3 fingers, the pharynx is open approximately 6 cm, the standing height is 4-5 fingers above the pubic articulation corresponds to the full disclosure of the uterine pharynx.

One of the important points in the management of childbirth is monitoring the condition of the fetus. Observation of the fetal heartbeat during the period of disclosure with an undisturbed fetal bladder is performed every 15-20 minutes, and after the outflow of amniotic fluid - after 5-10 minutes. It is necessary to carry out not only auscultation, but also the calculation of the fetal heart rate. With auscultation, attention is paid to the frequency, rhythm and sonority of heart sounds. Normally, the heart rate is 140 ± 10 per minute when listening.

Primiparous

Multiparous

At the place of the best listening to the fetal heartbeat, one can assume the position, presentation of the fetus, multiple pregnancy, as well as the extensor variant of the presentation of the fetal head.

The method of monitoring the fetal heart activity during childbirth has become widespread.

The use of intrapartum cardiotocography (CTG) is one of the diagnostic procedures that allows you to monitor the condition of the fetus and the contractile activity of the uterus during childbirth. Evaluation of cardiotocograms in labor has some features that differ from antenatal CTG. For the study, an external ultrasound sensor is attached to the anterior abdominal wall of the mother in the area where the fetal heart sounds are best heard. A strain gauge sensor for recording the contractile activity of the uterus is strengthened in the area of its fundus. In the normal state of the fetus, the basal rhythm of its heart rate remains within the normal range and with a cephalic presentation averages 120-160 per minute. During normal labor, regardless of the presentation of the fetus, the amplitude of the fetal heart rate oscillations varies and is 6-10 per minute, and their frequency is up to 6 per minute. The presence of accelerations on the cardiotocogram during childbirth is the most favorable sign indicating the normal state of the fetus (Fig. 5.21). With an uncomplicated course of childbirth and the physiological state of the fetus, accelerations are recorded in response to a contraction. The amplitude of accelerations is 15-25 per minute.

It is not always possible to obtain comprehensive information about the course of childbirth and cervical dilatation with some external methods. This information can be obtained using a vaginal examination of the woman in labor. Vaginal examination in the first stage of labor is performed at the first examination of the woman in labor, after the discharge of amniotic fluid, in the event of complications in the mother or fetus. Initially, the external genital organs (varicose nodes, scars, etc.) and the perineum (height, old tears, etc.) are examined. With a vaginal examination, the condition of the pelvic floor muscles (elastic, flabby), the vagina (wide, narrow, the presence of scars, septa), and the cervix is determined. The degree of smoothing of the neck (shortened, smoothed), whether the opening of the pharynx and the degree of opening (in centimeters), the state of the edges of the pharynx (thick, thin, soft or rigid), the presence of a site of placental tissue, a loop of the umbilical cord, a small part of the fetus within the throat are noted. With a whole fetal bladder, the degree of its tension during the contraction and pause is determined. Excessive tension, even during a pause, indicates polyhydramnios, flattening - to lack of water, flabbiness - to weakness of labor. Determine the presenting part of the fetus and identification points on it. In cephalic presentation, the sutures and fontanelles are probed and, according to their relation to the planes and sizes of the pelvis, they judge the position, presentation, insertion (synclitic or asynclitic), the presence of flexion (small fontanelle below the large one) or extension (large fontanelle below the small one, forehead, face).

If the presenting part is located high above the entrance to the pelvis and is not sufficiently accessible for the fingers in the vagina, then in such cases the examiner's other hand is pressed through the abdominal wall onto the presenting part, bringing it closer to the entrance to the small pelvis and thus making it accessible for examinations through the vagina. If recognition of the identification points on the presenting part is difficult (large birth swelling, strong configuration of the head, malformations) or presentation is unclear, an examination is performed with a "half-hand" (four fingers) or with the entire hand smeared with sterile petroleum jelly.

During a vaginal examination, in addition to identifying the identification points of the head, the features of the bony base of the birth canal are determined, the surface of the walls of the small pelvis is examined (whether there are deformations, exostoses, etc.).

Based on the vaginal examination, the ratio of the head to the planes of the pelvis is determined.

There are the following head positions: above the entrance to the pelvis, by a small or large segment at the entrance to the pelvis; in a wide or narrow part of the pelvic cavity, in the exit of the pelvis.

The head, located above the entrance to the small pelvis (Fig. 5.22), is mobile, moves freely with jolts (ballot) or is pressed against the entrance to the small pelvis. During vaginal examination, the head does not interfere with the palpation of the nameless lines of the pelvis, promontory (if accessible), the inner surface of the sacrum and the pubic articulation.

The fetal head with a small segment at the entrance to the small pelvis (Fig. 5.23) is motionless, most of it is located above the entrance to the pelvis, a small segment of the head is below the plane of the entrance to the pelvis. When applying the fourth method of external obstetric examination, the ends of the fingers converge, and the bases of the palms diverge. During vaginal examination, the sacral cavity is free; the cape can only be "approached" with a bent finger (if the cape is reachable). The inner surface of the pubic articulation is available for research.

The fetal head with a large segment at the entrance to the small pelvis (Fig. 5.24) means that the plane passing through the large segment of the head coincides with the plane of the entrance to the small pelvis. In an external obstetric examination, carried out by the fourth method, the palms are either parallel, or the ends of the fingers diverge. A vaginal examination reveals that the head covers the upper third of the pubic articulation and the sacrum, the promontory is unattainable, the sciatic spines are easily palpable.

If the head is located in the wide part of the small pelvis (Fig. 5.25), then the plane passing through the large segment of the head coincides with the plane of the wide part of the pelvis. During a vaginal examination, it is determined that the head is in its largest circumference in the plane of the wide part of the pelvic cavity, two-thirds of the inner surface of the pubic articulation and the upper half of the sacral cavity are occupied by the head. The GU and V sacral vertebrae and ischial spines are freely probed, i.e. identifying points of the narrow part of the pelvic cavity are determined.

If the head is located in a narrow part of the small pelvis (Fig. 5.26), then the plane of the large segment of the head coincides with the plane of the narrow part of the pelvis. The head above the entrance to the pelvis is not palpable. A vaginal examination reveals that the upper two-thirds of the sacral cavity and the entire inner surface of the pubic articulation are covered by the head of the fetus, the sciatic spines are difficult to reach.

The head is at the exit of the small pelvis - the plane of the large segment of the fetal head is at the exit of the pelvis. The sacral cavity is completely filled with the head, the ischial spines are not defined (Fig. 5.27).

The American school defines the relationship of the presenting part of the fetus to the planes of the small pelvis during its movement along the birth canal, using the concept of "levels" of the small pelvis. The following levels are distinguished:

1) the plane passing through the ischial spines - level 0;

2) planes passing 1, 2 and 3 cm above level 0 are designated respectively as levels - 1, -2, -3;

3) planes located 1, 2 and 3 cm below level 0 are designated as levels +1, +2, +3, respectively. At the +3 level, the presenting part is located on the perineum.

Volume at the entrance to the pelvis.

Page 8 of 43

Chapter 2
RADIOTELEMETRY OF INTRAUTERINE PRESSURE AND METHODS FOR ANALYSIS OF THE CONTRACTIVE ACTIVITY OF THE UTERUS IN THE PROCESS OF CHILDBIRTH. UTERINE CYCLE. BATTLE CLASSIFICATION
TECHNIQUE FOR REGISTRATION OF INTRAUTERINE PRESSURE OF LABOR WITH THE USE OF RADIOTELEMETRIC SYSTEMS
The radio telemetry system "Capsule" includes a receiving, analyzing and recording device (PARU) designed to receive radio signals emitted by microminiature radio transmitting devices called radio capsules, radio pills or endoradiosondes. The cylindrical sealed casing of the radio capsule 11-20 mm long and 8 mm in diameter contains a microsensor of pressure, pH or temperature, a transistor generator of high-frequency electromagnetic oscillations and a microminiature power source that ensures continuous operation of the capsule for 72-100 hours. The radio capsule emits radio signals, the frequency of which varies depending on the physiological parameter. To measure the pressure in the uterine cavity, a special modification of the radio capsule sensor has been created, which provides a measurement in the range of 0-26.6 kPa (0-200 mm Hg). The pH radio capsule allows you to measure the pH in the vagina or amniotic fluid in the range of 1-9.0. Temperature radio capsule allows continuous measurements within 34-42 ° С. Radio capsule signals are received at a distance of up to 1 m using an antenna located next to the woman in labor. Changes in physiological parameters are recorded on the moving tape of the recorder.
Registration of AMD in the process of I and II stages of labor is carried out as follows.

Rice. 5. Radiotelemetric registration of intrauterine pressure in I, II and III stages of labor (diagram).

After treatment for 5 minutes in 96% ethyl alcohol, the capsule is introduced during an internal obstetric examination into the uterine cavity above the contact belt of the presenting part with the entrance to the small pelvis with a whole amniotic fluid
bladder - extraamnially, with drained waters - intraamnially (Fig. 5).
Registration of SDM in the successive period is carried out using the same capsule according to the method, which is based on the method of measuring intraplacental venous pressure according to Moir [M. Ya. Blok, 1969]. Immediately after the birth of the child, the capsule is placed in a polyethylene tube filled with 5% sodium citrate solution, ending with a needle and clamp. After cutting the umbilical cord, the needle is inserted into the umbilical cord vein. The device is clamped to the umbilical cord. After the birth of the placenta, the final calibration of the radio capsule is carried out, which completes the study of the SDM in the I, II and III stages of labor (Fig. 6).

By the term "uterine cycle" we mean the phase of the contraction and the phase of the subsequent interval or functional “rest” of the uterus between contractions before the next contraction begins. The phase of the contraction, in turn, consists of a period of contraction, or "systole", - from the beginning of the contraction to the "peak" of the amplitude and a period of relaxation, or "diastole", - from the "peak" to the beginning of the phase of functional "rest" (Fig. 7) ...
In the process of analyzing tocograms, significant difficulties arise when trying to accurately divide the uterine cycle into a contraction phase and a relaxation phase. This is especially true for the tocograms of the discoordinated SDM. The reason for the difficulty is the absence in most cases of clear graphic signs of the beginning and end of the fight. N. Alarez and R. Ca1deyro-Barcia generally believed that the intervals between contractions should not be determined, since one contraction of the uterus gradually passes into another.
Attempts to isolate contractions at the points of a sharper change in the angles of the "curve" at the beginning and end of the fight, undertaken by A. Krarohl et al. (1970), from our point of view, are insufficiently substantiated, since the change in the angle depends not only on the features of uterine contractions, but also on the speed of movement of the tape drive mechanism of the recording device, as well as on changes in the vertical scales of the calibration graphs.
Studying the diagrams of many hours of recordings of AMD during childbirth, we came to the conclusion that it is necessary to clearly distinguish the phase of contraction and the phase of functional "rest" of the uterus, or the interval between contractions, on the SDM diagrams, which are the two main components of MC. For this purpose, we have applied the "threshold" method. The intersection of the horizontal line with the “curve” of the uterine cycle at the level of excess (“threshold”) of the minimum intrauterine pressure in the intervals between contractions by 0.266 kPa (2 mm Hg) allows separating the contraction from the period of functional “rest” of the uterus (see Fig. 7).

Rice. 7. Parameters of the uterine cycle (explained in the text). A-I period of childbirth; B-II period.

The choice of a value of 0.266 kPa (2 mm Hg) is associated with numerous determinations of the amplitudes of minor short-term fluctuations in pressure between contractions, as well as slower changes in the "tone" of the uterus. The clinical rationale for this methodological convention, which makes it possible to accurately and uniformly determine the duration of contractions and the intervals between them in labor, regardless of the experience of the researcher, lies in the fact that within the limits of the increase in intrauterine pressure up to 0.266 kPa (2 mm Hg) in comparison with the minimum level between contractions, the woman in labor does not experience pain. Palpation does not reveal changes in the tension of the muscles of the uterus, and electrophonocardiography of the fetus does not reveal any changes in cardiac activity.

Multi-channel external hysterography allows you to obtain information about the contractile activity of the uterus in its different parts.

The tone of the uterus, determined by hysterography, increases with the development of the labor process and is normally 8-12 mm Hg.

The interval between contractions decreases as labor progresses, amounting to 60 s. Normally, 4-4.5 contractions occur in 10 minutes.

Primiparous

Multiparous

The method of monitoring the fetal heart activity during childbirth has become widespread.

Based on the vaginal examination, the ratio of the head to the planes of the pelvis is determined.

1) the plane passing through the ischial spines - level 0;

2) planes passing 1, 2 and 3 cm above level 0 are designated respectively as levels - 1, -2, -3;

3) planes located 1, 2 and 3 cm below level 0 are designated as levels +1, +2, +3, respectively. At the +3 level, the presenting part is located on the perineum.

Volume at the entrance to the pelvis.

Disclosure period

It begins with the first regular contractions and ends with the full disclosure of the external uterine pharynx.

During contractions in the muscles of the uterus occur:

1). Contraction is the contraction of muscle fibers.

2). Retraction - displacement of them parallel to each other. In the intervals between contractions, this displacement remains. This causes stretching of the lower segment of the uterus and the opening of the external os of the uterus.

3). The contracting muscles of the uterine wall pull the circular muscles to the sides and up - distraction of the cervix occurs.

With each contraction, the uterine musculature presses on the contents of the ovum, an increase in intrauterine pressure occurs and amniotic fluid (namely, the "fetal bladder") rushes into the lower segment of the uterus and penetrates into the internal pharynx, acting as a hydraulic wedge.

With the development of strong contractions, the border between the contracting upper segment of the uterus and the stretching lower segments of the uterus begins to appear - the border ring.

Clearly, it is usually indicated after the discharge of amniotic fluid.

The opening of the throat occurs gradually - about 1 cm per hour. An opening of 10-12 cm is considered complete.

The place of coverage of the descending head of the fetus by the walls of the lower segment of the uterus is called the contact belt. He divides the amniotic fluid into the anterior (depart after rupture of the fetal bladder) and posterior.

Timely outpouring of water - if it happened with the full opening of the pharynx. If it happened before the full opening of the pharynx, then it is considered early, if before the onset of labor, it is premature, and if after the full opening of the pharynx, it is belated.

The intensity of contractions increases with the development of labor and normally in the first period ranges from 30 to 50 mm Hg. Art. In the second stage of labor, the intensity of uterine contractions decreases, but due to the addition of contractions of the striated muscles (pushing) it reaches 90-100 mm Hg. Art. Immediately after the birth of the child, the force of uterine contractions increases sharply, the intrauterine pressure rises to 70-80 mm Hg. Art., and intramyometral - up to 250-300 mm Hg, which contributes to the separation of the placenta.

The duration of contractions in the first stage of labor, according to their progression, increases from 60 to 100 s, in the second - it is approximately 90 s.

The interval between contractions decreases as labor progresses, amounting to about 60 seconds in the first stage of labor, and about 40 seconds in the second. Normally, 4-4.5 contractions occur in 10 minutes.

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Signs of the body's biological readiness for childbirth

Modern methods of registration of uterine contractile activity

2. Modern methods of registration of contractile activity

3. Etiology and classification of abnormalities of labor

Classification.

I. Pathological preliminary period.

II. Weakness of labor:

1. primary;

2. secondary;

3.weakness of attempts: primary, secondary

III. Excessive labor (overactive uterus).

IV. Discoordinated labor activity:

1.discoordination;

2. hypertonicity of the lower segment of the uterus (reversible gradient);

3.convulsive contractions (tetany of the uterus);

4. circular dystonia (contraction ring).

4. Pathological preliminary period

Clinic of the pathological preliminary period:

1) cramping pains in the lower abdomen, sacrum and lower back, irregular in frequency, duration and intensity, lasting more than 6 hours;

2) the woman's sleep and wakefulness is disturbed, she is tired, exhausted;

3) during external examination: the tone of the uterus is increased, especially in the lower segment, parts of the fetus are poorly palpated;

Diagnostics is based on:

1) anamnesis;

2) external obstetric examination;

3) vaginal examination;

4) hysterographic data (contractions of various strengths and durations are recorded at unequal intervals);

5) cytological examination of the vaginal smear (cytotype I or II is detected, which indicates insufficient estrogen saturation).