Prevention of early-term deliveries: much ado about nothing?

The timing of birth is a critical determinant of perinatal outcome. Both preterm birth (delivery 42-0/7 weeks) are associated with an increased risk for adverse pregnancy outcomes. The American Congress of Obstetricians and Gynecologists (ACOG) has engaged in a sustained campaign over the past few years to make elective delivery prior to 39 weeks a “never event,” a campaign that has been very successful. But have its efforts been too successful? The primary focus of this campaign has been to prevent induction of labor prior to 39 weeks of gestation, without adequately emphasizing that this applies only to elective inductions. As a result, many indicated deliveries are being unnecessarily delayed, thereby putting the lives of both mothers and fetuses at risk. Just last week, I was called by a provider who wanted some advice. He had a patient at 38-3/7 weeks with a complete placenta previa who presented with vaginal bleeding, but was reluctant to proceed with delivery because she was not yet at 39 weeks of gestation. And the week prior, while visiting an affiliate hospital, I noticed that a patient with a prior classical cesarean delivery had been scheduled for her elective repeat cesarean after 39 weeks. In response to such unanticipated consequences, ACOG and the Society for Maternal-Fetal Medicine (SMFM) recently published a series of consensus opinions to better define when it is and is not appropriate to deliver a patient in the “late-preterm” (34-0/7 to 36-6/7 weeks) or “early-term” (37-0/7 to 38-6/7 weeks) period.1–3 Some of the recommendations are precise and offer clear guidance to practitioners on when to effect delivery within a narrow gestational age window, whereas others are so broad and generic as to be unhelpful (Table 1). And then there are some conditions (such as cholestasis of pregnancy) that are not mentioned at all. In addition, as the key opinion leaders who authored these committee opinions readily concede, all the recommendations are based on “limited or inconsistent scientific evidence” (class B evidence).1–3 Interestingly, no allowance is made for documentation of fetal lung maturity. Indeed, amniocentesis for fetal lung maturity is strongly discouraged.1–3 Table 1 Recommended Timing of Delivery for Select Pregnancy Complications Infants born at 37 weeks of gestation do not fare as well as infants born at 39 weeks of gestation. Compared with infants born at 39 weeks, those born in the early-term period have higher rates of short-term complications, including respiratory distress syndrome (RDS), pneumonia, hypoglycemia, and neonatal intensive care unit admission.3 However, RDS at 37 weeks of gestation does not have the same implications as RDS at 27 weeks, the former requiring an average of only 1 day of ventilatory support with no long-term consequences.4 The absolute risk of long-term sequelae following delivery at 37 weeks of gestation is extremely low. For example, the incremental increase in neonatal mortality between 37 and 39 weeks of gestation is estimated at 1 per 10,000 live births.3,5 In contrast, around 7 per 10,000 fetuses will suffer stillbirth in the 2-week interval from 37 to 39 weeks of gestation (an absolute increase from 2.5 to 9.1 stillbirths per 10,000 deliveries).3,6 This translates in absolute terms to more than 2000 stillbirths between 37 and 39 weeks of gestation each year in the United States alone, and reminds us that many more lives are lost from stillbirth than from complications of prematurity and sudden infant death syndrome combined.7 Delivery at 37 weeks of gestation does, therefore, confer some benefit over delivery at 39 weeks. Although elective delivery prior to 39 weeks of gestation cannot be routinely recommended, practitioners should individualize management when circumstances dictate. When a woman presents at 38 weeks of gestation complaining of decreased fetal movements, a factor known to be associated with stillbirth,8 serious consideration should be given to proceeding with induction of labor. The ACOG recommendations are not intended to trump clinical judgment or supersede physician discretion. They are simply guidelines. Instead of talking about elective delivery prior to 39 weeks of gestation as a “never event,” the message to practitioners should be to use this option sparingly (< 2% of deliveries) and only after careful and thorough consideration and counseling.