Methods of preparing pregnant women for childbirth

The state of readiness for childbirth is most clearly revealed by changes found in the female's reproductive system. 

Determination of cervical maturity

To diagnose the changes that occur during the formation of readiness for childbirth in the body of a woman, the following tests were most widely used:

• definition of the maturity of the cervix;
• study of the physical and chemical properties of cervical mucus;
• refinement of parameters of contractile activity of the uterus, its sensitivity to oxytocin;
• cytological examination of vaginal smears and others. However, of all the tests listed above, the most reliable and easily feasible method is the palpation determination of the maturity of the cervix. At the same time pay attention to the consistency (degree of softening) of the cervix, the length of the vaginal part of it, the degree of gaping of the cervical canal, the position of the cervix with respect to the axis of the pelvis. In the gaping cervical canal, the degree of its patency is determined, as well as its length, comparing this indicator with the length of the vaginal cervix: the smaller the difference between the marked indicators, the more pronounced the maturity of the cervix.

All these characteristics are the basis of the classification developed by prof. G. G. Khechinashvili. According to this classification, the following four types of cervical condition should be considered.

1. Immature cervix uteri - softened only around the periphery and dense in the course of the cervical canal, and in some cases dense whole; The vaginal part is retained or slightly shortened. The external sore is closed or passes the tip of the finger; the vaginal part is represented as "fleshy", the thickness of its wall is about 2 cm. The cervix is located in the cavity of the small pelvis, away from the wire axis of the pelvis and the median line of it, the outer part of it is determined at a level corresponding to the middle distance between the upper and lower edges of the pubic articulation or even closer to its upper edge.
2. The maturing cervix of the uterus is not completely softened, the area of the dense tissue along the neck canal is still determined, and especially at the level of the internal pharynx. The vaginal part of the cervix is slightly shortened, the tip of the finger passes through the first-born external sap, or less often the cervical canal is passed for the finger to the internal pharynx, or with difficulty for the inner pharynx. Attention is drawn to the significant difference (more than 1 cm) between the length of the vaginal part of the cervix and the length of the cervical canal. There is a sharp transition of the cervical canal to the lower segment in the region of the internal pharynx.

The present part is palpated through the arches not clearly enough. The wall of the vaginal cervix is still fairly thick (up to 1.5 cm), the vaginal part of the cervix is located away from the wire axis of the pelvis. The external sill is determined at the level of the lower edge of the symphysis or somewhat higher.

3. The not fully ripened cervix is softened almost completely, only in the area of the internal pharynx is still determined the area of the dense tissue, the canal in all cases passes for one finger for the inner pharynx, in the primiparous with difficulty. There is no smooth transition of the cervical canal to the lower segment. The present part is palpated through the arches quite distinctly.

The wall of the vaginal part of the cervix is markedly thinned (up to 1 cm), and the vaginal part itself is located closer to the wire axis of the pelvis. The external sill is determined at the level of the lower edge of the symphysis, and sometimes even lower, but does not reach the level of sciatic fossae.

4. The mature cervix is completely softened; is shortened or sharply shortened, the cervical canal freely passes one finger and more, does not bend, smoothly passes to the lower segment of the uterus in the region of the internal pharynx. Through the vaults, the presenting part of the fetus is clearly enough palpable.

The wall of the vaginal part of the cervix is considerably thinned (up to 4-5 mm), the vaginal part is located strictly along the wire axis of the pelvis; External sores are determined at the level of sciatic lobes.

If there is a bad or insufficiently expressed maturity of the cervix (especially in the first and second of its varieties), the spontaneous onset of labor in the near future is unrealistic. In women who have an uncomplicated course of pregnancy, at the time of onset of labor, a poor or insufficiently expressed maturity of the cervix is only found in 10% of cases. In all these women, spontaneously initiated births acquire a pathological - protracted course due to the development of discoordinated labor with manifestations of cervical dystopia.

Signs of maturity of the uterus can be expressed in points and calculate the forecast index

Symptom	Points
	1	2	3
The position of the cervix with respect to the axis of the pelvis	To the rump	Median	In the wire line
Cervical length	2 cm and more	1 cm	Smoothed
Consistency of the cervix	Thick	Softened	Soft
Opening of the external pharynx	Closed	1-2 centimeters	3 cm
Locations of the fetus	Above the entrance	Between the upper and lower edge of the womb	Lower edge of the heart and below

When assessing 0-5 points, the cervix is considered immature if the sum of the scores is more than 10 - the cervix is mature (ready for childbirth) and you can apply rhodium excitement.

[1]

Evaluation of the tone and contractility of the uterus

For the purpose of recording the tone of the uterus and its contractile activity in pregnant women and parturient women, many methods known as external and internal hysterography methods have been proposed.

Methods of internal hysterography allow us to judge the contractile activity of the uterus according to the indices of intrauterine pressure.

Less difficult to apply and completely harmless methods of external hysterography (tocographies), based on the use of various sensors applied to the abdominal wall.

The vast majority of these methods do not give an accurate idea of the tone and contractile activity of the uterus. The methods of external hysterography mostly allow us to judge only the frequency of fights and partly about their duration, and with multichannel leads - about the coordination of contractions of various sections of the uterus. Recently, the most common method is cardiotocography.

[2], [3], [4], [5], [6]

Determination of the sensitivity of the uterus to oxytocin

It is known that the reactivity of the uterus to oxytocin as the pregnancy progresses gradually increases and reaches a maximum immediately before childbirth. In 19S4 Smith was the first to use this phenomenon, having developed a special test for determining the reactivity of the myometrium for intravenous administration of a threshold dose of oxytocin, which can cause uterine contraction. Subsequently, this dose was named by him oxytocin test or test of sensitivity of the uterus to oxytocin, the technique of which is as follows.

Before using the test for 15 minutes, the woman in question should be in a horizontal position, in a state of complete emotional and physical rest to exclude the possibility of contractions of the uterus under the influence of various factors. Immediately before the test, a solution of oxytocin is prepared based on 0.01 units of action (ED) of the preparation per 1 ml of isotonic sodium chloride solution, 10 ml of this solution is injected into the syringe and intravenous injection is started. The author does not recommend the introduction of a solution of oxytocin immediately after venepuncture, since carrying out the latter in itself can cause a reduction in the uterus. The author recommends that the solution be injected "jerkily" at 1 ml at a time, with intervals between each such injection of 1 min. In general, you can enter no more than 5 ml of solution. The administration of the solution should be stopped with the appearance of the uterine reaction (its contraction).

The test is considered positive if the oxytocin-induced uterine contraction appears within the first 3 min from the start of the test, i.e., by administering 1, 2 or 3 ml of the solution. Abbreviations of the uterus are recorded either with palpation of the abdomen, or using one of the methods of hysterography.

According to Smith, a positive oxytocin test indicates the possibility of a spontaneous onset of labor in a woman within the next 1-2 days. The author recommends the use of the oxytocin test also for the purpose of determining a woman's readiness for delivery before using the labor excitement for the purpose of preterm delivery for various indications. The reactivity of the uterus to oxytocin in this test does not depend on the age of the woman being studied and whether it is the first or the reproductive one.

Oxytocin test has found wide application both in clinical practice and in scientific research.

Some authors have modified Smith's method of conducting the oxytocin test somewhat. Thus, Baumgarten and Hofhansl (1961) consider it expedient to make an intravenous injection of a solution of oxytocin not "jerky", but gradually, at 0.01 ED in 1 ml of isotonic sodium chloride solution in 1 min. From the point of view of these authors, this method of administering the oxytocin solution is more physiological and prevents the possibility of tetanic contraction of the uterus. Klimek (1961), taking as a basis the original method Smith, suggested by the number of ml of the injected solution of oxytocin (capable of causing a reduction in the uterus) to judge how many days after counting from the date of the sample, we should expect a spontaneous onset of labor. So, if the contraction of the uterus occurs after intravenous injection of 2 ml of oxytocin solution (0.02 U), the delivery should occur after 2 days.

Thus, according to the above studies, the oxytocin test is valuable for diagnosing a woman's readiness for childbirth and determining the conditions for performing labor excitement when early termination of pregnancy is necessary.

Recently, it has been widely accepted before induction to carry out a so-called stress oxytocin test, which makes it possible to evaluate not only the readiness of the uterus for contractile activity, but also to determine the fetus's condition.

[7], [8], [9], [10], [11]

Cytological examination of vaginal smears

It is now generally accepted that the method of cytological examination of vaginal smears can be used to determine the qualitative changes in the hormonal balance of the female body during pregnancy and especially before the onset of labor. Extensive literature is devoted to this subject.

For completeness of judgments about the qualitative changes in the composition of cells of the vaginal content of a woman in the dynamics of pregnancy, polychromy must be used to color the smears, which makes it possible to differentiate cyanophilic cells from zosinophilic cells. It is generally believed that the detection in the smear of predominantly cyanophilic cells indicates a predominance of progesterone activity over estrogens. Conversely, the increase in the content of zosinophilic cells indicates an increase in the activity of estrogens.

In recent years, the method of luminescent microscopy of vaginal smears has been applied. However, despite the relative simplicity and speed of its implementation, the negative side of this method, as well as the method using the usual (monochrome) color of the smears, is that they both do not allow to judge the change in the quantitative content of cyanophilic and zosinophilic cells.

During pregnancy, especially beginning with the second trimester, the basal layer of the epithelium proliferates and the growth of the epithelium increases, while the number of cells in the surface layer decreases. All these changes are associated with the increasing activity of placental steroids and especially progesterone. By this time, navicular (navicular) cells, characteristic of pregnancy, appear from the intermediate layer of the vaginal epithelium. A distinctive feature of scaphoid cells is the vacuolization of the cytoplasm due to the accumulation of glycogen in it, as well as pronounced cyanophilia. A significant predominance of scaphoid, cyanophilic staining and closely adjacent cells is observed in a physiologically occurring pregnancy before the term of 38-39 weeks.

Starting from the 38-39th week of pregnancy (about 10 days before the forthcoming birth), changes appear in the cytological picture of the vaginal smear, attributed to an increase in the activity of estrogen hormones with a simultaneous decrease in the activity of progesterone. As the delivery approaches, the number of typical sciatic-shaped cells typical for progressive pregnancy decreases with an increase in the number of cells in the surface layers, increasingly colored eosinophilically and containing pycnotic nuclei. In this case, there is also a rarefaction of cellular elements, a decrease in the ability of epithelial cells to perceive the paint and the appearance of an increasing number of leukocytes.

Evaluation of the listed cell elements makes it possible to determine the belonging of each studied smear to one of the four cytotypes cited in the classification of Zhydovsky (1964), and to judge the degree of biological readiness of the woman for childbirth.

Below is a brief description of the data of microscopy of vaginal smears, typical for each cytotype; At the same time, the expected terms of the onset of labor, which are characteristic of each cytotype, are also indicated.

• I cytotype: "late pregnancy" or "navicular type of smears" is typical for a normally progressing pregnancy, beginning with its II trimester. In the smear, navicular and intermediate cells predominate in the 3: 1 ratio in the form of characteristic clusters. The cytoplasm of such cells is sharply cyanophilic. There are almost no surface cells in the smear. Leukocytes and mucus, as a rule, are absent.

Eosinophilic cells occur on average in 1% of women, and cells with pycnosis of nuclei - up to 3%.

The onset of labor with this cytotype of smears should be expected no earlier than 10 days after the day they were taken.

• II cytotype: "not long before delivery." In a smear of this type, the number of scaphoid cells decreases with a simultaneous increase in the number of actually intermediate cells, and their ratio is 1: 1. Cells begin to be located more isolated, and not in the form of clusters, as is observed in the smear typical of the first cytotype.

The number of surface cells increases, and among them the number of eosinophilic cells and cells with pycnosis of nuclei increases slightly (up to 2% and up to 6%, respectively).

The onset of labor with this type of smears should be expected in 4-8 days.

• III cytotype: "term of delivery". In a smear of this type, intermediate (up to 60-80%) and superficial (up to 25-40%) cells with bubble-like or pycnotic nuclei predominate. Scaphoid cells are found only in 3-10 %. There are no accumulations of cells, and the latter are located in isolation. The content of eosinophilic cells increases to 8%, and cells with pycnosis of nuclei - up to 15-20%. The amount of mucus and leukocytes is also increasing. The colorability of the cells is reduced, and their contours are less contrasting.

The onset of labor with this type of smears should be expected after 1-5 days.

• IV cytotype: "the unquestionable period of birth *. Smears show the most pronounced regressive changes: surface cells predominate (up to 80%), scaphoid cells are almost absent, and a small number of proprietary cells are actually present. Surface eosinophilic cells sometimes lose their nuclei and have the appearance of "red shadows". The cytoplasm is mostly poorly colored, the edges of the cells are low contrast, and the smear acquires the appearance of "erased" or "dirty". The number of eosinophilic cells increases to 20%, and cells with pycnosis of nuclei - up to 20-40%. Noticeably increases the number of leukocytes and mucus in the form of clusters.

Childbirth with this type of smears should occur on the same day or, as a last resort, within the next three days.

Change in some physical and biochemical properties of the secretion of the glands of the cervix uteri at the end of pregnancy as an indication of the readiness of the woman's organism for delivery

In pregnant women, in contrast to non-pregnant women, there are some features of the secretion of the glandular apparatus of the cervix. Kogai (1976) showed that at the 32-36th week of pregnancy in the presence of a maturing cervix of the uterus, that is, in the absence of its readiness for childbirth, there is little mucus in the cervical canal (the "dry" neck), and she sucked with difficulty. The mucus in such cases is opaque and does not crystallize upon drying, that is, the symptom of "fern" is absent. In addition, during these periods of pregnancy, compared with later, mucus contains a relatively small amount of total protein. In the presence of maturing cervix in 32-36 weeks of pregnancy, protein fractions are detected: albumin, transferrin, immunoglobulin.

As we approach the forthcoming births and the maturity of the cervix increases, a distinct change in the physical and biochemical properties of mucus is observed: its quantity increases and transparency grows. Every third woman, 1-2 days before the birth, is found to have crystallized cervical mucus.

With almost full pregnancy and the detection of the mature cervix, starting from the 38-39th week, the total protein content in the cervical mucus increases and a rich protein spectrum is found. So, if during pregnancy 32-36 weeks in mucus 1-3 protein fractions are detected, then before birth it contains 8-10 such fractions.

Thus, during the maturation of the cervix, there are significant changes in the function of the glands of the cervical canal, which is manifested by a significant increase in the total amount of mucus to be separated, the increase in its transparency, the appearance of the crystallization symptom, the increase in its total protein content and the expansion of its spectrum. These changes in the secretory function of the cervical glands may, apparently, be used as an additional test in assessing the degree of readiness of the female organism for childbirth.

[12], [13], [14]