This is a corrected version of the article that appeared in print.
Am Fam Physician. 2022;105(2):177-186
Author disclosure: No relevant financial relationships.
Induction of labor is a common obstetric procedure, and approximately one-fourth of pregnant patients undergo the procedure. Although exercise and nipple stimulation can increase the likelihood of spontaneous labor, sexual intercourse may not be effective. Acupuncture has been used for labor induction; however, it has not been shown to increase vaginal delivery rates. There is strong evidence that membrane sweeping can increase the likelihood of spontaneous labor within 48 hours. Cervical preparation or ripening is often needed before induction. Some evidence shows that the use of nonpharmacologic approaches such as osmotic dilators and cervical ripening balloons reduce time to delivery. The effect of amniotomy on labor is uncertain. Pharmacologic intervention with oxytocin or prostaglandins is effective for cervical ripening and induction of labor. Combining a balloon catheter with misoprostol is a common practice and has been shown to decrease time to delivery in a small study.
| Recommendation | Sponsoring organization |
|---|---|
| Do not schedule non–medically indicated (elective) inductions of labor or cesarean deliveries before 39 weeks 0 days gestational age. | American Academy of Family Physicians American College of Obstetricians and Gynecologists |
Indications for Induction
Induction of labor is indicated when the risks of continuing the pregnancy outweigh the risks of induction, with the goal of delivery while minimizing risks to the mother and newborn. Maternal, fetal, and placental conditions can increase the risk of continuing a pregnancy. Common medical indications for induction of labor and recommended timing are covered in Table 1.4 [corrected]
| Indication | Suggested timing (weeks' gestation) | |
|---|---|---|
| Earliest | Before | |
| Maternal | ||
| Chronic hypertension | ||
| No medications | 38 | 40 |
| Well controlled | 37 | 40 |
| Poorly controlled or proteinuria | 36 | 38 |
| Gestational hypertension | 37 | At diagnosis if later than 37 |
| Preeclampsia | ||
| No severe features | 37 | At diagnosis if later than 37 |
| Severe features (immediate if unstable) | 34 | At diagnosis if later than 34 |
| Prepregnancy diabetes mellitus | ||
| Well controlled | 39 | 40 |
| Well controlled but vascular disease | 36 | 39 |
| Poorly controlled | 36 | 39 |
| Gestational diabetes | ||
| Well controlled with diet (A1) | 39 | 41 |
| Well controlled with medication (A2) | 39 | 40 |
| Poorly controlled | Individualized | |
| Cholestasis of pregnancy | 36 | 39 |
| HIV infection (if viral load ≤ 1,000 copies per mL) | 39 | — |
| Fetal | ||
| Fetal growth restriction | ||
| Single gestation, no issues | 38 | 39 |
| Single gestation, other conditions | 34 | 38 |
| Twin gestation, no issues | 36 | 38 |
| Twin gestation, monochorionic or other condition | 32 | 35 |
| Oligohydramnios | 36 | 38 |
| Polyhydramnios | 39 | 41 |
| Alloimmunization | 37 | 39 |
| Multiple gestation | ||
| Dichorionic diamniotic | 38 | 39 |
| Monochorionic diamniotic | 34 | 38 |
| Monochorionic monoamniotic | 32 | 34 |
| Obstetric | ||
| History of stillbirth | Individualized | |
| Late term | 41 | 42 |
| Note: The placental disorders placenta previa, vasa previa, and invasive placental disorders were removed from this table because all typically require cesarean delivery. | ||
Induction of labor before 39 weeks' gestation increases neonatal morbidity and mortality and is not recommended without a medical indication.5,6 Several studies demonstrate that induction of labor at 41 weeks leads to similar outcomes as induction at 42 weeks. Pregnancies that exceed 42 weeks' gestation have increased neonatal morbidity, including convulsions, meconium aspiration, and need for intensive care.7
TIMING OF ELECTIVE INDUCTION
Until recently, elective inductions before 41 weeks' gestation have been controversial because of a lack of evidence. A large randomized trial showed that elective inductions at 39 weeks' gestation or later are associated with improved outcomes in first pregnancies.8 In this trial of low-risk nulliparous women, elective induction at 39 weeks to 39 weeks 4 days had similar neonatal mortality and morbidity as delivery at 40 weeks 5 days or later. Infants from the elective induction group had less need for respiratory support, with a number needed to treat (NNT) of 83 to prevent respiratory support in the first 72 hours of life.
There were also several other improved outcomes with elective induction. Elective induction reduced cesarean delivery (NNT = 28 to prevent one cesarean delivery) and reduced hypertensive pregnancy disorders (NNT = 17).8 The Society for Maternal-Fetal Medicine and the American College of Obstetricians and Gynecologists endorse offering elective induction of labor at 39 weeks' gestation to low-risk nulliparous pregnant individuals under circumstances that are consistent with this trial's study protocol.9,10
INDUCTION OF LABOR AFTER PRIOR CESAREAN DELIVERY
There are several reasons for choosing a trial of labor after a cesarean delivery (TOLAC) instead of a repeat cesarean delivery, including shorter hospital stay, shorter recovery time, and reduced pain after delivery. Careful counseling is required before TOLAC because of risks, including uterine rupture.11,12 A validated calculator is available to assist when deciding on TOLAC vs. a repeat cesarean delivery (https://mfmunetwork.bsc.gwu.edu/web/mfmunetwork/vaginal-birth-after-cesarean-calculator). This calculator was updated to remove the race and ethnicity component, which does not affect the validity.13
For individuals who have had one prior cesarean delivery, TOLAC may reduce rates of cesarean delivery.14–16 In 2019, the American Academy of Family Physicians reaffirmed clinical practice guidelines for management of TOLAC (https://www.aafp.org/family-physician/patient-care/clinical-recommendations/all-clinical-recommendations/vaginal-birth-after-cesarean.html). Cervical ripening balloons and oxytocin (Pitocin) are appropriate agents for TOLAC, but prostaglandin use increases the risk of uterine rupture and should be avoided.1,17,18
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