Early-Term Elective Delivery May Be OK, Study Suggests

By Troy Brown, RN
Medscape Medical News

Infants born electively at 37 to 38 weeks' gestation are not at increased risk for neonatal morbidity or infant mortality compared with infants who are expectantly managed and born at 39 weeks' gestation or older, according to a population-based retrospective cohort study of more than 600,000 infants. However, the researchers did see elevated rates for adverse outcomes among the subset of infants delivered by elective cesarean.

Jason L. Salemi, PhD, MPH, from the Department of Family and Community Medicine, Baylor College of Medicine, Houston, Texas, and colleagues report their findings in an article published online March 9 in Obstetrics & Gynecology.

The study findings run counter to current recommendations from the American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine. A joint committee opinion specifies, "Although there are specific indications for delivery before 39 weeks of gestation, a nonmedically indicated early-term delivery is not appropriate."

"In contrast to the current dogma, we found that when a methodologically appropriate comparison group was used, elective induction before 39 weeks of gestation was not associated with an increased likelihood of adverse outcomes," the researchers write.

Dr Salemi and colleagues contend that previous studies have used inappropriate comparison groups. "By comparing elective early-term deliveries with later term spontaneous deliveries alone, studies may be overestimating adverse effects of elective early-term delivery. Because the clinical decision that must be made is a choice between elective early-term delivery and expectant management, in which the later delivery outcome remains unknown, the appropriate comparison group should consist of all infants who were candidates for elective early-term delivery but whose deliveries occurred at a later gestational age."

The researchers classified the infants into either a control group born at 39 to 40 weeks of gestation after expectant management or one of four early-term (37 - 38 weeks' gestation) delivery groups: infants who were born by electively induced delivery, elective cesarean delivery without a trial of labor, spontaneous delivery, and medically indicated delivery.

Most of the infants (64.6%) were born full-term. Among the babies born early-term, 50% were born after spontaneous onset of labor (n = 112,846) and 40% were delivered after elective induction (n = 33,213) or cesarean birth (n = 55,515).

Overall, 51,846 (8.2%) infants experienced an adverse outcome, the most prevalent of which was respiratory morbidity (5.98%; 95% confidence interval [CI], 5.92% - 6.04%). The neonatal intensive care unit (NICU) admission rate was 2.61% (95% CI, 2.57% - 2.65%). The infant mortality rate was 1.46 per 1000 live births (95% CI, 1.37 - 1.56), with 928 infant deaths. Neonatal sepsis (1.34%; 95% CI, 1.31% - 1.37%) and feeding difficulties (1.26%; 95% CI, 1.23% - 1.29%) occurred at approximately the same rate.

"Across all morbidities, the early induced group had rates that were similar to the full-term group. Conversely, the early cesarean delivery group experienced higher rates of each outcome than the full-term group and, for respiratory morbidities and NICU admissions, approximately doubled the rate of the early induced group," the researchers write.

After adjustment for potential confounders, babies born after early induction did not have an increased risk for respiratory morbidity, neonatal sepsis, or NICU admission compared with the full-term babies, but they did have an increased risk for feeding difficulty (odds ratio [OR], 1.18; 99% CI, 1.02 - 1.36).

Odds for all morbidity outcomes were higher among infants in the early cesarean delivery group, however. The increase in risk for neonatal sepsis relative to the full-term group was only 13% (OR, 1.13; 99% CI, 1.01 - 1.27) but it was 66% higher for respiratory morbidity, 51% higher for NICU admission, and 36% higher for feeding difficulties.

"Although our findings of no difference in the odds of several adverse outcomes among early inductions contradict much of the published literature, our results are in general agreement with the few studies that have used a methodologically appropriate comparison group," the researchers write.

"The issues that surround the timing and reasons for delivery initiation are complicated and each pregnancy unique," the authors conclude. "This study adds to a small but growing body of literature that cautions against a general avoidance of all elective early-term deliveries and fosters support for continued research, based on better data, in this still relatively new arena."

The study was supported by a grant from the Agency for Healthcare Research and Quality. The authors have disclosed no relevant financial relationships.

Obstet Gynecol. 2016;127:657-666.