NEW YORK (Reuters Health) – There are benefits to electing to induce labor at 39 weeks gestation in low-risk women who have already given birth, according to two new studies.
Dr. Rachel Sinkey and colleagues from the University of Alabama at Birmingham took a look back at 3,703 low-risk multiparous women who each delivered a single baby between 39 and 42 weeks gestation. Of these, 12% delivered between 39 0/7 and 39 4/7 after an elective induction of labor and the remainder in the expectant-management group delivered at 39 5/7 weeks or later.
Compared with expectant management, elective induction of labor was associated with fewer cases of a perinatal composite of death, neonatal respiratory support, 5-minute Apgar score of 3 or less, and shoulder dystocia (4.0% vs. 7.1%; adjusted odds ratio, 0.57; 95% confidence interval, 0.34 to 0.96).
There were also fewer cesarean deliveries with elective induction of labor (5.1% vs. 6.6%; aOR, 0.60; 95% CI, 0.37 to 0.97), with no difference in other maternal outcomes (hypertensive disorders, chorioamnionitis, and operative vaginal deliveries) or admissions to neonatal intensive-care units.
“I was intrigued by our findings, but am mindful that this was an observational study,” Dr. Sinkey commented by email to Reuters Health. “I believe this needs to be studied prospectively across various populations to learn more. Our promising findings can be included in counseling women on the pros and cons, but other studies have shown induction in nulliparous women results in longer times on labor and delivery (which were unavailable for this paper), which may not be desirable for some women. In sum, elective induction may be an option for multiparous women, but additional prospective studies are needed,” said Dr. Sinkey.
In the other study, published online today in Obstetrics and Gynecology along with the first, researchers analyzed U.S. vital-statistics data for 5.4 million low-risk parous women who delivered single infants at 39 (54.4%), 40 (35.7%), or 41 (9.9%) weeks’ gestation.
The overall rate of the composite neonatal adverse outcome (Apgar score less than 5 at 5 minutes, assisted ventilation for longer than six hours, neonatal seizure, or neonatal mortality) was 4.86 per 1,000 live births.
The risk was higher in women who delivered at 40 weeks (adjusted relative risk, 1.18; 95% CI, 1.15 to 1.22) and 41 (aRR 1.59; 95% CI, 1.53 to 1.65) weeks gestation compared with 39 weeks.
The overall rate of the composite maternal adverse outcome (ICU admission, blood transfusion, uterine rupture, or unplanned hysterectomy) was 2.31 per 1,000 live births. This risk was also significantly higher with delivery at 40 weeks (aRR 1.15; 95% CI, 1.11 to 1.19) and 41 weeks gestation (aRR 1.50; 95% CI, 1.42 to 1.58) than at 39 weeks.
“We hope that clinicians would accept that even among seemingly low-risk parous women, continuing pregnancy beyond 39 weeks is associated with multiple adverse outcomes to the newborn and themselves,” lead authors Dr. Han-Yang Chen and Dr. Suneet Chauhan from McGovern Medical School at the University of Texas, in Houston, wrote in a joint email to Reuters Health. “We also hope that the clinicians would share the data with the women they manage.”
They added, “In absence of a randomized clinical trial among low-risk parous women, it is difficult to generalize and formulate guidelines. Nonetheless, our analysis suffices for shared decision making and informing low-risk women about the risks of continuing pregnancy beyond 39 weeks and the potential benefits of induction.”
SOURCE: http://bit.ly/32oG3II and http://bit.ly/2Ju8T2L
Obstet Gynecol 2019.