Whether induction of labor ahead in low-risk women improves pregnancy outcomes?: A retrospective cohort, observational study

Abstract

The appropriate timing of delivery for pregnancies has always been a concern for medical staff, and the timing of elective labor induction at 41 weeks in low-risk pregnant women has always been controversial. We compared maternal and fetal outcomes between gestational age at 40 0/7 to 40 6/7 and 41 0/7 to 41 6/7 weeks. This retrospective cohort study was conducted at the obstetrics department of Jiangsu Province Hospital from January 1 st to December 31 st in 2020. Maternal medical records and neonatal delivery data were collected. One-way analysis of variance, Mann–Whitney U test, χ 2 test, Fisher exact test and logistig regression analysis were performed. The study included 1569 pregnancies, with 1107 (70.6%) delivered at 40 0/7 to 40 6/7 weeks and 462 (29.4%) delivered at 41 0/7 to 41 6/7 weeks. Intrapartum cesarean section (8% vs 16%, P < .001), meconium-stained amniotic fluid (13% vs 19%, P = .004), episiotomy (41% vs 49%, P = .011), and macrosomia (13% vs 18%, P = .026) were significantly lower at 40 0/7 to 40 6/7 weeks. The premature rupture of membranes rate (22% vs 12%, P < .001), vaginal delivery rate of artificial rupture of membrane induction (83% vs 71%, P = .006) and balloon catheter combined with oxytocin induction (88% vs 79%, P = .049) were significantly higher at 40 0/7 to 40 6/7 weeks. Low-risk women who delivered at 40 0/7 to 40 6/7 weeks showed better outcomes in terms of the mother’s and baby’s health, such as decreased rates of intrapartum cesarean section, meconium-stained amniotic fluid, episiotomy, and macrosomia, compared with those who delivered at 41 0/7 to 41 6/7 weeks.

Maternal and Perinatal Outcome After Induction of LaborVersusExpectant Management in Low-risk Pregnancies Beyond Term

“…For the evaluation of the maternal outcomes, we initially analyzed the mode of delivery depending on gestational age. Here, we could show that the rate of secondary c-section increased with advanced gestational age, which is supported by other published studies (3,12,28). Corresponding, the rate of spontaneous deliveries decreased whereas the rate of vaginaloperative deliveries remained unchanged.…”

“…With respect to different recommendations of current national guidelines depending on the gestational age (26), we analyzed the data within the subgroups 40+0-40+6 weeks, 40+7-40+10 weeks and >40+10 weeks. This classification is also in line with prior national retrospective studies (2, 27) and similar to other international studies (10,12,13,28). The strength of our study is the large number of singleton low-risk pregnancies beyond term which corresponds to a usual cohort in a university perinatal center.…”

“…All other parameters defining maternal outcome in our study stress the favorable maternal outcome in the period under review. In detail, the need for epidural anesthesia and tocolysis subpartu was independent from gestational age, but significantly increased subsequent to the induction of labor, which is consistent with other studies (12,14,15,21,28,37,39). According to published data, induction of labor reduced the duration of labor compared to expectant management (15,32), which was inconsistent with our study.…”

“…Furthermore, there is evidence for strong increase of perinatal mortality in postterm pregnancies (6,7). However, retrospective data indicate that risk of perinatal morbidity and mortality does not appear rapidly but develops continuously from the 39 th gestational week (6,(8)(9)(10)(11)(12)(13). Therefore, taking into account additional data from randomized clinical trials (14,15), several national guidelines implemented recommendations for induction of labor at 41 weeks or even support induction of labor at or beyond 37 gestational weeks (16,17).…”