ABSTRACT: The neonatal risks of late-preterm and early-term births are well established, and the potential neonatal complications associated with elective delivery at less than 39 0/7 weeks of gestation are well described. However, there are a number of maternal, fetal, and placental complications in which either a late-preterm or early-term delivery is warranted. The timing of delivery in such cases must balance the maternal and newborn risks of late-preterm and early-term delivery with the risks associated with further continuation of pregnancy. Deferring delivery to the 39th week is not recommended if there is a medical or obstetric indication for earlier delivery. If there is a clear indication for a late-preterm or early-term delivery for either maternal or newborn benefit, then delivery should occur regardless of the results of lung maturity testing. Conversely, if delivery could be delayed safely in the context of an immature lung profile result, then no clear indication for a late-preterm or early-term delivery exists. Also, there remain several conditions for which data to guide delivery timing are not available. Some examples of these conditions include uterine dehiscence or chronic placental abruption. Delivery timing in these circumstances should be individualized and based on the current clinical situation.

Recommendations

The American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine make the following recommendations:

• Deferring delivery to the 39th week is not recommended if there is a medical or obstetric indication for earlier delivery. Table 1 presents recommendations for the timing of delivery for a number of specific conditions.

• In the case of an anticipated late-preterm delivery, a single course of antenatal betamethasone is recommended within 7 days of delivery in select women who have not received a previous course of antenatal corticosteroids. However, a medically indicated late-preterm delivery should not be delayed for the administration of antenatal corticosteroids.

Introduction

The American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine have long discouraged nonindicated delivery before 39 weeks of gestation. The reason for this longstanding principle is that the neonatal risks of late-preterm (34 0/7–36 6/7 weeks of gestation) and early-term (37 0/7–38 6/7 weeks of gestation) births are well established, and the potential neonatal complications associated with elective delivery at less than 39 0/7 weeks of gestation are well described 1 2. Based on these and other data, timing of elective delivery at 39 weeks of gestation or later is recommended 3.

However, there are a number of maternal, fetal, and placental complications in which either a late-preterm or early-term delivery is warranted. The timing of delivery in such cases must balance the maternal and newborn risks of late-preterm and early-term delivery with the risks associated with further continuation of pregnancy. Deferring delivery to the 39th week of gestation is not recommended if there is a medical or obstetric indication for earlier delivery. To address the issue of appropriate indications for delivery at less than 39 weeks of gestation, the Eunice Kennedy Shriver National Institute of Child Health and Human Development and the Society for Maternal-Fetal Medicine convened a workshop that summarized the available evidence and made recommendations 4. This Committee Opinion integrates the findings in this report, as well as more recent evidence, to provide recommendations regarding timing of delivery for frequent obstetric, maternal, fetal, and placental or uterine conditions that would necessitate delivery before 39 weeks of gestation. Still, the evidence regarding timing of indicated delivery for most conditions is limited, with recommendations based largely on expert consensus and relevant observational studies.

There are several important principles to consider in the timing of delivery. First, the decisions regarding delivery timing are complex and must take into account relative maternal and newborn risks, practice environment, and patient preferences. Second, late-preterm or early-term deliveries may be warranted for maternal benefit or newborn benefit, or both. In some cases, health care providers will need to weigh competing risks and benefits for the woman and her fetus. For these reasons, and because the recommendations for timing of delivery are based on limited data, decisions regarding timing of delivery always should be individualized to the needs of the patient. Additionally, recommendations for timing of delivery before 39 weeks of gestation are dependent on an accurate determination of gestational age.

Amniocentesis for the determination of fetal lung maturity should not be used to guide the timing of delivery, even in suboptimally dated pregnancies 5. The reasons for this are multiple and interrelated. First, if there is a clear indication for a late-preterm or early-term delivery for either maternal or newborn benefit, then delivery should occur regardless of the results of lung maturity testing. Conversely, if delivery could be delayed safely in the context of an immature lung profile result, then no clear indication for a late-preterm or early-term delivery exists. Second, mature amniotic fluid indices are imperfect in the prediction of neonatal respiratory outcomes and are not necessarily reflective of maturity in other organ systems 6.

In the case of an anticipated late-preterm delivery, a single course of antenatal betamethasone is recommended within 7 days of the delivery in select women who have not received a previous course of antenatal corticosteroids 7. However, a medically indicated late-preterm delivery should not be delayed for the administration of antenatal corticosteroids.

Table 1 presents recommendations for the timing of delivery for many specific conditions. This list is not meant to be all-inclusive, but rather is a compilation of indications commonly encountered in clinical practice. “General timing” describes the concept of whether a condition is appropriately managed with either a late-preterm or early-term delivery. “Suggested specific timing” refers to more defined timing of delivery within the broader categories of late-preterm or early-term delivery. These are recommendations only and will need to be individualized and reevaluated as new evidence becomes available. Also there remain several conditions for which data to guide delivery timing are not available. Some examples of these conditions include uterine dehiscence or chronic placental abruption. Delivery timing in these circumstances should be individualized and based on the current clinical situation. In situations in which there is a wide gestational age range for acceptable delivery thresholds, the lower range is not automatically preferable and medical decision making for the upper or lower part of a range should depend on individual patient factors and risks and benefits. Not uncommonly, a patient may have multiple indications for possible late-preterm or early-term delivery. The American College of Obstetricians and Gynecologists has developed an applet https://www.acog.org/membership/member-benefits/acog-app to address and adjudicate competing delivery indications.