Secondary cervical dilatation

Secondary cervical dilatation can be recorded when the maximum opening on the Friedman curve in the active phase of delivery is stopped for 2 hours or more.

Diagnostics

In order to diagnose a secondary cervical dilatation, at least two vaginal examinations are required at 2-hour intervals, confirming that there is no disclosure during this time period. The stop should be recorded during the maximum lift phase on the neck-opening curve so as not to confuse it with the protracted latent phase (a violation that occurs when the maximum lift phase has not yet started) or a delayed deceleration (a violation noted when the maximum lift phase has already ended ).

[1], [2]

Frequency

The most common disturbance observed during the active phase of labor is secondary arrest of cervical dilatation, which is observed in 6.8% of primiparous and in 3.5% of moles. According to E. Friedman et al. (1978), it is observed somewhat more often - 11.7% for primiparous and 4.8% for maternity females. In any case, this abnormality of labor is more common in primiparous women and is often a component of such situations, when several anomalies of labor are observed simultaneously.

Causes

With a secondary cervical dilatation stop in about 50% of cases, the etiological factor is the discrepancy between the size of the fetus and the pelvis of the woman in labor. Such a high frequency of nonconformity leads to a rigorous assessment of the ratio of fetal and pelvic maternal size in each case when this anomaly of labor is detected. Another etiological factor is the incorrect position of the fetal head, as well as excessive anesthesia and regional anesthesia. Quite often there is a combination of two or more of these factors, including inconsistency.

[3], [4], [5], [6], [7]

Forecast

The high frequency of mismatch between fetal and pelvic dimensions in parturient women with a secondary cervical dilatation stop causes with caution to speak out about the prognosis of these conditions. With the help of pelvimetry, it is possible to determine the absolute inconsistency of the sizes in 25-30% of women with this abnormality of labor. After a fairly active attempt to normalize the course of the latter, it turns out that even in 10-15% of parturient women (most of whom have borderline mismatch of fetal and pelvic dimensions of the mother), there is no effect of treatment and they require the completion of labor by caesarean section. In the remaining parturient women (approximately 55%), the birth ends through natural birthmarks.

Leading begins with the determination of the ratio of fetal and pelvic maternity sizes to confirm the presence of inconsistency and exclusion of unnecessary and potentially dangerous stimulation of labor.

The most important clinical technique used to assess the ratio of fetal and pelvic dimensions of the mother (the existing methods for estimating the disparity in fetal and pelvic dimensions of the mother - rhenopetiometry, echography, nuclear magnetic resonance, etc. - are not sensitive enough) is the sample proposed by Gillis and Muller. To do this, the obstetrician performs vaginal examination before the fight or at the very beginning. When the peak of the contraction is reached, an attempt is made to push the presenting part of the fetus into the small pelvis by pressing a free hand on the bottom of the uterus. At the same time, the hand inserted into the vagina, trying to determine the possible lowering into the small pelvis of the parturient of the presenting part of the fetus, when jerking the doctor's free hand on the abdominal wall in the area of the uterine fundus. If the present part moves very little or does not move at all, then the probability of a discrepancy between the size of the fetus and the pelvis of the mother is very high. If the present part easily moves into the small pelvis, then the discrepancy is unlikely.

In parturients with a secondary labor stop and limited mobility of the fetus in the Gillis-Muller test, it is recommended to perform an evaluation using radiographic pelvimetry, which makes it possible to diagnose an absolute mismatch between the fetal and pelvic dimensions of the mother and exclude further attempts at delivery through natural birthmarks in approximately 1/3 of parturient women secondary cervical dilatation. Another 1/3 of women giving birth are borderline indicators, 1/3 there is no discrepancy in size. When confirming the clinical inconsistency, it is necessary to perform a cesarean delivery without further delay.

If the pelvic and fetal head sizes (positive Gillis-Muller test, pelvimetry) match, stimulation of labor with internal hysterography, direct electrocardiography of the fetus and determination of the actual pH from the fetal head is required. Most of these women giving birth have a decreased activity of the uterus and a reasonable use of oxytocin allows you to eliminate the violations associated with the stopping of labor, and to achieve a normal birth of the fetus.

In some parturient women with secondary cervical closure and normal or borderline pelvimetry results (as in the Gillis-Muller and X-ray studies), a fairly good labor activity is observed (fights every 2-2.5 minutes with a duration of 60 s, pressure at the height of the bout more than 50 mm of pg.). There are conflicting opinions about the management of such pregnant women.

Some midwives in this pathology consider uterus activity to be quite satisfactory, and additional stimulation is undesirable and even sometimes dangerous. According to others, the activity of the uterus is reduced, since it does not lead to a sufficient opening of the cervix; in the absence of a disparity between the size of the pelvis and the fetal head, in many cases, successful cautious (!) stimulation is possible , since the use of oxytocin in parturient women with sufficiently effective labor can be dangerous and should be carried out with extreme caution.

Treatment should start with the introduction of oxytocin 0.5 mU / min, and if a thorough evaluation does not reveal signs of hyperstimulation or threatening fetal status, you can periodically increase the dose of the drug by 0.5 mU / min at an interval of 20 minutes. In such cases, do not exceed the maximum dose of 0.5 mU / min.

With this management of women in childbirth, the question arises: how long and in what quantities should oxytocin be administered to increase the activity of labor. Almost all the parturient women have an effect within the 6-hour stimulation period, although 85% had a positive reaction within the first 3 hours. A positive reaction in response to stimulation is characterized by the appearance of a rise on the cervical opening curve. Therefore, a 3-hour period of normal activity of the uterus (after a stop) creates sufficient conditions for the restoration of labor activity in parturient women with a secondary cervical opening stop receiving oxytocin treatment.

If, after a 3-hour period of stimulation and more active labor, there is no further exposure to the cervix, subsequent attempts to achieve delivery through natural birth canals are unfounded and labor should be terminated by a caesarean section.

With a good effect of oxytocin stimulation, the rise in the cervical dilatation curve after a stop can be the same or even higher than before. In these cases, the prognosis is favorable and there are all possibilities for conducting vaginal delivery.

If there is no reaction to oxytocin or an increase in the opening curve of the cervix less than before the stop, the situation must be seriously overestimated, since in many such cases, at the first evaluation, a discrepancy was observed between the size of the fetus and the pelvis of the mother. It is necessary to repeat the Gillis-Muller method and carefully analyze the radiographs and the results of pelvimetry to establish the source of the error. As a rule, a disproportion between the size of the pelvis and the fetal head is usually detected and a caesarean section should be performed.

There are some differences in the nature and outcome of the secondary cervical dilatation stopping, depending on the time of its development in the process of birth. Indeed, early arrest is often associated with a mismatch between the size of the fetus and the pelvis of the mother and requires surgical intervention much more often than the stop that appeared in the active phase of childbirth. In addition, when there is a good response to stimulation with oxytocin at an early stop, the rise in the cervical dilatation curve after a stop is usually higher than noted before, and there is an excellent chance for vaginal delivery. In other words, infrequently early stopping is amenable to correction, but those cases in which a good reaction to oxytocin is observed have a favorable prognosis.

When the cervix is repeatedly stopped, the birth should be completed by a caesarean section, unless it can be established that there are other factors other than a mismatch (epidural anesthesia, an overdose of sedatives) that could cause a second stop.

[8], [9], [10], [11], [12]