Inducing labor at 39 weeks of pregnancy has the greatest benefit in risk reduction for women from more socioeconomically deprived areas, according to a new study published in the open access journal PLOS Medicine by Ipek Gurol-Urganci of the London School of Hygiene & Tropical Medicine, U.K., and colleagues. The findings suggest that increased uptake of induction of labor at 39 weeks may help reduce inequities in adverse perinatal outcomes.

Adverse perinatal outcomes—which include stillbirths, neonatal deaths, preterm births, and other birth complications—are more common among women from deprived areas and ethnic minorities in England. There is ongoing debate about whether induction of labor with birth at 39 weeks should be offered in low-risk pregnancies based on ethnicity or socioeconomic status.

In the new study, researchers analyzed a database of all maternal admissions in the English National Health Service between January 2018 and March 2021. A total of 501,072 women with low-risk pregnancies who had not yet given birth at 39 weeks were included in the analysis; of these, 47,352 (9.5%) had induction of labor at 39 weeks.

Of births in the induction group, 3.3% had an adverse perinatal outcome compared to 3.6% of births in the expectant management group . After adjustment, researchers found a small benefit from induction of labor in low-risk pregnancies, with 360 inductions associated with the avoidance of one adverse outcome. However, the benefits of induction were mainly seen in women from more socioeconomically deprived areas (p=0.01) and women with no previous pregnancies (p=0.02).

"Improved collection of routine data on the indication for induction and the presence of risk factors is required to corroborate the role that induction of labor at 39 weeks in women with a low-risk pregnancy can play in reducing inequalities in risk of adverse perinatal outcomes," co-author Prof. Asma Khalil says.

Dr. Ipek Gurol-Urganci adds, "We used routinely collected administrative hospital data. Our study highlighted that we urgently need detailed, accurate and complete data from each maternity unit, collected at national level, especially about the indications of induction of labor, so that we get an even better understanding of the role that induction of labor can play in improving perinatal outcomes."