Impact Of Elective Induction Of Labor On Maternal And Neonatal Outcomes In Late-term Pregnancy

Background:Elective induction of labor(eIOL)is defined as inductions of labor in the absence of medical or obstetrical indications.Term pregnancies are artificially divided into early-term pregnancies(37 0/7 to 38 6/7 weeks),late-term pregnancies(39 0/7 to 40 6/7 weeks),and postterm pregnancies(41 0/0 to 41 6/7 weeks).The guidelines recommend that induction of labor after 41 0/7 weeks of gestation can be considered and discourage nonindicated delivery before 39 0/7 weeks of gestation given reducing maternal and prenatal adverse outcomes of early-term deliveries.Early studies suggest that induction of labor is associated with increased odds of cesarean delivery in comparison with spontaneous labor which is not a certain alternative to labor induction and gives little insight into the correlation based on ignoring women who give birth due to medical indications.A randomized,controlled,unblinded,clinical trial of a large sample shows that eIOL at 39 weeks in low-risk nulliparous women results in a lower frequency of cesarean delivery than expectant management(EM)with queries of the applicability out of the setting.Additional studies are needed where there is a dearth of studies on eIOL in China.Objective:To analyze the association of eIOL at term compared with expectant management and maternal and neonatal outcomes towards exploring optimal management of term pregnancy.Methods:This is a retrospective study of a total of 501 singleton deliveries at term at Qilu Hospital of Shandong University(April 1,2020,to September 30,2020).We divide the sample by gestational age of induction of labor and management into 4 groups including eIOL group(n=54,nulliparous 36,multiparous 18)and EM group(n=218,nulliparous 143,multiparous 75)at 390/7 to 39 6/7 weeks,eIOL group(n=135,nulliparous 92,multiparous 43)and EM group(n=94,nulliparous 60,multiparous 34)at 40 0/7 to 40 6/7 weeks.We compare general characteristics,managements and other information between the eIOL and EM groups at different weeks of gestation.The binary logistic regression is used to analyze the impact of eIOL on maternal and neonatal outcomes.Outcomes:1.There is no significant difference between the eIOL and EM group in terms of age,prenatal body mass index,parity,and the Bishop scores(P>0.05).2.The eIOL group at 39 weeks does result a higher frequency of the combination of oxytocin and medicines for promoting cervical ripening compared to the EM group.(20.4%vs.4.3%,P=0.018)。The eIOL group does result in a higher frequency of using mebendazole(nulliparous at 39 weeks with 27.8%vs.9.9%,P<0.01;nulliparous at 40 weeks with 32.6%vs.16.1%,P<0.05;multiparous at 39 weeks with 27.8%vs.9.9%,P<0.01).The eIOL group is more likely to have a cesarean section due to failed induction(40.0%vs.12.0%,P<0.05),while the EM group is more likely to undergo cesarean delivery due to fetal distress.Intervention indications in the EM group are mainly premature rupture of membranes,fetal distress,and delayed pregnancy.3.The eIOL group at 39 weeks in nulliparous women results in a significantly higher frequency of cesarean delivery(OR=2.44;95%CI 1.03-5.74)where the indications for cesarean delivery are predominantly fetal distress and failed induction of labor and are associated with a significantly lower frequency of meconium-stained amniotic fluid of third-degree(OR=0.18;95%CI 0.04-0.81).There is no significant difference between the eIOL and EM groups in other adverse outcomes such as vaginal surgical assistance and postpartum hemorrhage(P>0.05).4.There is no significant difference between the eIOL and EM groups in terms of adverse outcomes such as macrosomia,neonatal jaundice and neonatal asphyxia(P>0.05).Conclusions:1.The eIOL at 39 0/7 to 39 6/7 weeks for multiparous women or at 40 0/7 to 40 6/7 weeks for nulliparous women and multiparous women may be a reasonable option because the eIOL does not increase the risk of adverse maternal and neonatal outcomes.2.Be cautious about the eIOL for nulliparous women at 39 0/7 to 39 6/7 weeks which may increase the risk of cesarean delivery.