Does a policy of inducing labor at 37 weeks or more of gestation reduce the risks for infants and their mothers compared with a policy of waiting until a later gestational age or until Will there be indications for labor induction?

This review was originally published in 2006 and subsequently updated in 2012 and 2018.

What is the problem?

The average pregnancy lasts 40 weeks from the start of a woman's last menstrual period. Pregnancies lasting more than 42 weeks are described as "post-term" and therefore the woman and her doctor may decide to give birth by induction. Factors associated with postnatal pregnancy and delayed delivery include obesity, first birth, and maternal age over 30 years.

Why is this important?

Protracted (term) pregnancy may increase risks for infants, including greater risk of death (before or shortly after birth). However, induction (stimulation or induction) of labor can also pose risks to mothers and their babies, especially if the woman's cervix is ​​not ready for delivery. Current diagnostic methods cannot predict risks to babies or their mothers per se, and many hospitals have specific policies regarding how long a pregnancy can last.

What evidence did we find?

We searched for evidence (July 17, 2019) and identified 34 randomized controlled trials in 16 different countries involving more than 21,500 women (mostly at low risk of complications). The trials compared a policy of induction of labor after 41 completed weeks of gestation (>287 days) with a policy of waiting (expectant management).

Labor induction policies were associated with fewer perinatal deaths (22 trials, 18 795 babies). Four perinatal deaths occurred in the induction policy group compared with 25 perinatal deaths in the expectant management group. Fewer stillbirths occurred in the induction group (22 trials, 18,795 infants): two in the induction group and 16 in the expectant management group.

Women in the induction of labor groups in the included studies were probably less likely to deliver by caesarean section than in the expectant management groups (31 studies, 21,030 women), and there was probably little or no difference when compared with assisted vaginal delivery (22 studies, 18,584 women).

Fewer infants were admitted to the neonatal intensive care unit (NICU) in the induction policy group (17 trials, 17,826 infants; high-certainty evidence). A simple test of the baby's health status (Apgar score) at five minutes after birth was likely to be more favorable in the induction groups than expectant management (20 trials, 18,345 infants).

An induction policy may make little or no difference for women who have had a perineal injury, and likely has little or no effect on the number of women with postpartum hemorrhage or breastfeeding at hospital discharge. We are uncertain about the effect of induction or expectant management on length of stay in the maternity hospital due to the very low certainty of the evidence.

Among newborns, the number of children with trauma or encephalopathy was similar in both groups (moderate and low-certainty evidence, respectively). None of the studies reported the development of neurodevelopmental problems during follow-up of children and postpartum depression in women. Only three trials reported some measure of maternal satisfaction.

What does this mean?

An induction policy compared to expectant management is associated with fewer infant deaths and probably fewer caesarean sections; and probably has little or no effect on assisted vaginal delivery. Determining the best time to offer induction of labor to women at 37 weeks' gestation or more requires further study, as well as further study of women's risk profiles and their values ​​and preferences. Discussing the risks of induction of labor, including benefits and harms, can help women make an informed choice between induction of labor, especially if the pregnancy lasts more than 41 weeks, or expectant management—waiting and/or waiting until labor is induced. Women's understanding of induction, procedures, their risks and benefits is important to influence their choice and satisfaction.

Translation notes:

Translation: Alekseeva Lada Igorevna. Editing: Prosyukova Ksenia Olegovna and Ziganshina Lilia Evgenievna. Russian translation project coordination: Cochrane Russia - Cochrane Russia, Cochrane Geographic Group Associated to Cochrane Nordic. For questions related to this translation, please contact us at: [email protected]

Labor induction. When is it really needed?

Sokolova Elena

Published: 02/14/2023

Reading time: 7 minutes

3686

When should labor be induced?

Most pregnant women are set for spontaneous delivery. But what to do if the date of birth is approaching, has come, or even passed, and the birth has not begun. Or the doctor talks about the need for delivery, and the delivery date is still far away. In this article we will talk about the stimulation of the birth act. We will analyze the indications and discuss why induction of labor is performed.

To begin with, let's understand what is the induction (stimulation) of labor. Under the induction of labor understand the artificial stimulation of the onset of labor. That is, the launch of labor activity, which occurs after the introduction of drugs, the use of measures. An important factor that is assessed before induction is the assessment of the degree of maturity of the cervix (assessed by the doctor during a vaginal examination). After all, the cervix indicates the readiness of the woman's body for childbirth. Well, if the body is ready, and there is no time to wait for the spontaneous start of the start of labor, then you can start it.

But what to do if there are indications for delivery, there are no contraindications for vaginal delivery, and the cervix is ​​immature? Simply put, it is necessary to give birth, but the body is not yet ready. Caesarean section cannot be considered as an alternative to spontaneous delivery. There are strict indications for it. After a caesarean section, the recovery period increases, the risk of complications increases, a scar remains on the uterus, there is no breastfeeding for the first day (separation of mother and child), a belated arrival of primary milk is often noted. The answer is simple. In such situations, activities are carried out aimed at accelerating the maturation of the cervix - pre-induction of childbirth.

Naturally, all activities are carried out only with the written consent of the pregnant woman. Before suggesting labor induction, the physician always states the reason why this management option is being considered. Indications, contraindications, individual factors are taken into account. If you feel like saying no, I'll wait for spontaneous labor to develop, stop. Ask your doctor to tell you more about the indication for labor induction in your case. Specify what can happen to you and the baby if you refuse and continue to wait. Make a decision carefully, without unnecessary emotions.

Before deciding whether to induce labor, the doctor evaluates the situation:

• The patient's history (operations on the uterus, cervix, the number of pregnancies and their outcome, the presence of somatic diseases ...). Since often a complicated anamnesis is a contraindication to induction of labor.

• Recalculates the gestational age (the doctor once again makes sure that the gestational age is accurate). The tendency to overbearing remains the most common reason for induction of labor. Therefore, the exact determination of the gestational age is fundamentally important in this matter.

• Interprets the result of CBC, OAM, hemostasiograms, blood biochemical parameters. Changes in laboratory parameters often require additional examination, consultation of narrow specialists, and decision on management tactics only after the final diagnosis is made.

• Obstetric examination allows to determine the position of the fetus, the presenting part, the height of the presenting part. With the pelvic, oblique and transverse position of the fetus, high standing of the presenting part, induction of labor is not carried out.

• Cervical maturity is assessed by vaginal examination. This is an important and separately assessed factor during the decision to induce labor. The degree of maturity of the cervix is ​​assessed according to the Bishop scale:

Obtaining a test result of 8 or more points indicates a mature cervix. The mature cervix is ​​shortened to 1-2 cm, passes a finger to the internal os in primiparas and beyond the internal os in multiparous, soft, located along the axis of the pelvis, the fetal head is pressed. An insufficiently mature cervix is ​​estimated at 6-7 points. About an immature cervix say 5 or less points (the body is not ready for childbirth) - the cervix is ​​​​long, dense, the cervical canal is closed or misses the tip of a finger in a multiparous woman, is rejected backwards.

Vaginal examination also evaluates the integrity of the amniotic sac, the capacity of the pelvis, and the nature of the discharge. With an opened fetal bladder, the doctor individually approaches the tactics of managing the patient, taking into account a combination of factors. With a decrease in the capacity of the pelvis, the doctor faces the task of additional examination in order to resolve the issue of the possibility of delivery through the natural birth canal. The presence of pathological discharge is always alarming and gives rise to further examination.

• A smear is taken for the flora and the degree of purity of the vagina to exclude an infectious and inflammatory process.

• If necessary, other methods of examination are carried out, narrow specialists are invited for consultation.

• CTG of the fetus, dopplerography is performed

• Based on the data obtained, the doctor will decide on further tactics of pregnancy management, preparation for childbirth, method of delivery, delivery.

Let's find out when the doctor suggests labor induction. That is, consider the indications:

• Immature cervix at 41 weeks and 4-5 days of gestation (this is the most common indication). Further expectant management increases the percentage of complications in childbirth, both on the part of the mother and the fetus.

• Premature rupture of amniotic fluid. Prolonged lack of development of labor activity increases the risk of complications.

• Moderate pre-eclampsia

• Isosensitization by Rh factor or ABO system. Prolongation of pregnancy increases the risk of fetal complications against the background of the progression of the conflict.

• Mother's diseases, including oncological ones, against which prolongation of pregnancy is inappropriate.

• Fetal death

There are also contraindications to labor induction (mainly these are conditions in which vaginal delivery is impossible or is accompanied by an increased risk for the mother and (or) fetus):

• Anatomically narrow pelvis grade 2-3 (or 1 with a pelviography result of a discrepancy between the size of the pelvis and the size of the fetal head)

• Transverse, oblique, pelvic presentation of the fetus 070

• Multiple pregnancies

• Multiparous (5 or more births in history)

• Operations on the uterus and (or) cervix

• Tumors of the uterus, cervix, vagina, preventing the passage of the fetus through the natural birth canal

• Somatic diseases of the mother in the stage of decompensation

• Subcompensated or decompensated fetoplacental insufficiency, progressive hypoxia of the fetus indications for delivery through natural birth ways

Ways to induce labor

At the stage of vaginal examination, the doctor determines the maturity of the cervix and evaluates the results on the Bishop scale. This is what will be fundamental in resolving the issue of the need for pre-induction (methods aimed at accelerating the maturation of the cervix) or induction (methods aimed at starting labor).

The purpose of pre-induction is to ripen the cervix. For pre-induction, medical methods and dilators of the cervical canal are used.

Medical methods include the synthetic progesterone antagonist mifepristone. All women are well aware, and many have taken progesterone preparations during pregnancy (utrogestan, duphaston). The action of progesterone is aimed at maintaining pregnancy. But the time of childbirth comes, and hence the change of the dominant hormone. We need a hormone of the opposite action - a progesterone antagonist. The action of Mifepristone is aimed at the maturation of the cervix and the start of labor. It is prescribed only by the attending physician for an immature or insufficiently mature cervix in a hospital setting.

Preparations of the prostaglandin group also belong to the medical pre-induction of labor. Gel Dinoprostone. What are prostaglandins? These are polyunsaturated fatty acids derived from arachidonic acid. Contains arachidonic acid in red meat, poultry, fish, oils. This is a note to you and a reminder of the importance of a balanced diet. Prostaglandins contribute to the maturation of the cervix, stimulate the contractile activity of the uterus. The level of prostaglandins rises before childbirth, but especially in childbirth. Dinoprostone is administered intravaginally (into the posterior fornix of the vagina) for an immature cervix and intracervically (into the cervical canal) for an insufficiently mature cervix. The gel is prescribed and administered only by an obstetrician-gynecologist.

Non-pharmacological methods include Dilapan-S dilator. It is a dense synthetic gel in the form of a rod. The gel is injected into the cervical canal. The action of the gel is based on the absorption of fluid from the cervix. The diameter of the rod gradually increases, mechanically expanding the cervical canal. Against the background of tissue stretching, a cascade of reactions is triggered, leading to the maturation of the cervix and the development of labor.

Foley catheters. Based on mechanical pressure. A catheter is inserted through the cervical canal. The catheter balloon is filled with isotonic saline. Under the action of mechanical pressure, the cervix opens, the production of prostaglandins increases, the maturation of the cervix and the development of regular labor activity are stimulated.

Against the background of activities aimed at maturation of the cervix (pre-induction), there is a high probability of the development of regular labor activity. The birth act starts.

Induction of labor (stimulation of labor) is performed on the mature cervix. The cervix may be mature initially upon admission to the hospital or mature during pre-induction.

When should one think about labor induction (labor stimulation)?

Naturally, only if there are indications, no contraindications, the written consent of the woman and against the background of a mature cervix.

Time passes, the cervix is ​​mature, there are indications for induction, there are no contraindications, the woman signed the consent - it's time for induction of labor.

In the modern world, induction of labor is not seen as something extraordinary. Timely induction of labor allows avoiding a number of complications both from the side of the mother and from the side of the fetus, to give birth to a baby through the natural birth canal, which is undoubtedly the most favorable. So how can a doctor help start labor

• Amniotomy (opening the membranes of the membranes of the membranes) is one of the methods of labor induction. It is carried out by an obstetrician-gynecologist and is absolutely painless for a pregnant woman. During and after the amniotomy, the production of oxytocin, prostaglandins increases, the presenting part is pressed against the internal pharynx, making mechanical pressure. All this leads to the launch of labor activity (usually after a few hours).

• Administration of oxytocin. Oxytocin is a hormone that is produced in the hypothalamus, enters the pituitary gland, and then into the bloodstream. Its concentration in the blood increases before childbirth. The action of oxytocin is aimed at increasing the contractility of the myometrium, which leads to the development of regular labor activity. With a reduced concentration of the hormone in the blood, the development of labor activity is delayed. The introduction of synthetic oxytocin (an exact analogue of natural) leads to the development of regular labor activity. It is prescribed only by an obstetrician-gynecologist and is carried out under the monitoring of the fetus and mother.

• Combination of amniotomy and oxytocin. After the amniotomy is completed, oxytocin is administered intravenously.

How long does labor induction last?

When will it start? This question is asked by all women who are preparing the cervix and stimulating labor.

Many schemes have been developed to induce labor and prepare the cervix. This may be the effect of one drug, method, or a combination of them. When choosing a scheme, the obstetrician-gynecologist considers an individual approach in each case. It depends on the degree of maturity of the cervix, indications and contraindications, the obstetric situation, the woman's consent to the events.

In some situations, the waiting time for the development of regular labor activity can be limited to a day, for example, in case of premature rupture of amniotic fluid and there are no indications for an emergency caesarean section. In others, you can wait 3 days or add other methods of induction (pre-induction), for example, with a tendency to overbearing in the absence of indications for operative delivery in a particular situation.

The majority of pregnant women develop regular labor even during the preparation of the cervix.

If the cervical ripening method fails, the doctor will consider another method (combined method) or a caesarean section.

If combined approaches to the maturation of the cervix do not give a positive effect, then the option of delivery remains caesarean section.

With a positive effect from the preparation of the cervix (the cervix is ​​​​characterized as mature), the doctor recommends and performs (naturally after the written consent of the patient) labor induction.

The development of regular labor activity against the background of preparation and (or) stimulation of labor does not always guarantee delivery through the natural birth canal. Emergency indications for operative delivery may appear, as in women whose childbirth began spontaneously.

Conclusions

1. There are clear indications and contraindications for labor induction.

2. Before you make a decision, ask the doctor all the questions you are interested in, specify why you are offered this option. And only after receiving full information, make decisions.

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