妊娠39周引产对初产妇剖宫产率及母婴不良结局的影响

Effect of Induction of Labor at 39 Gestational Weeks on Cesarean Delivery Rate and Adverse Maternal and Neonatal Outcomes in Nulliparous Women

目的:探讨妊娠39周引产相对常规妊娠41周引产对初产妇剖宫产率及母婴不良结局的影响。方法:回顾性收集上海市浦东新区妇幼保健院2017年1月1日至2021年2月28日收治的918例孕产妇的临床资料,均为妊娠39周以上引产分娩、单胎、头位且无明确增加母婴不良结局的妊娠合并症及并发症的初产妇。根据引产孕周分为妊娠39周组(184例)、妊娠40周组(384例)以及妊娠41周组(350例)。对3组间产妇一般情况、促子宫颈成熟情况、引产方式及不同子宫颈成熟(子宫颈评分≥4分,子宫颈评分<4分)的产程时间进行比较;对3组间剖宫产率、剖宫产指征、母婴不良结局进行Log-binomial回归分析。结果:①3组初产妇年龄、孕次、孕前体质量指数(BMI)、产前BMI差异均无统计学意义(P>0.05);孕期增重随引产孕周增加而增加(P<0.05);3组的引产指征、促子宫颈成熟、引产方式的情况差异均有统计学意义(P<0.05)。②3组发生剖宫产的风险差异无统计学意义(P>0.05),引产失败比例随孕周增加而升高(P<0.05)。③与妊娠41周组比较,妊娠39周组(RR 0.71,95%CI 0.56~0.89)、妊娠40周组(RR 0.78,95%CI 0.65~0.92)的新生儿综合不良结局的风险均降低。子宫颈评分<4分时,3组进入产程时间、总产程时间、引产到分娩时间差异均无统计学意义(P>0.05);当子宫颈评分≥4分时,妊娠39周引产进入产程时间、总产程时间和引产到分娩时间均短于妊娠40周及妊娠41周(P<0.05)。结论:妊娠39周引产在不增加剖宫产率的情况下或可降低部分母婴不良结局的发生率。

Objective:This study aimed to compare the effects of induction of labor at 39 weeks versus 41 weeks of gestation on cesarean section rate and adverse outcomes for mothers and newborns in nulliparous women.Methods:We retrospectively collected clinical data of 918 nulliparous mothers who underwent induction of labor at 39 weeks or more of gestation,with singleton,cephalic presentation and no specific risk factors for adverse pregnancy outcomes,at Shanghai Pudong New Area Health Care Hospital for Women and Children from January 1,2017 to February 28,2021.Patients were divided into three groups according to gestational weeks:induction group at 39 weeks(184 cases),induction group at 40 weeks(384 cases)and induction group at 41 weeks(350 cases).We compared the general characteristics of the mothers,the cervical ripening methods,the induction modes and the labor duration for different cervical ripening levels(Bishop score≥4 points,Bishop score<4 points)among the three groups.We also performed Log-binomial regression analysis to compare the cesarean section rate,the indications for cesarean section and the adverse outcomes for mothers and newborns among the three groups and calculated the relative risk(RR).Results:①There was no significant difference in age,gravidity,pre-pregnancy body mass index(BMI)or prenatal BMI among the three groups(P>0.05).Gestational weight gain increased with increasing gestational weeks of induction(P<0.05),and there was a significant difference in the indications for induction,cervical ripening methods and induction modes among the three groups(P<0.05).②There was no significant difference in the risk of cesarean section among the three groups(P>0.05),but the proportion of failed induction rose with increasing gestational weeks(P<0.05).③Compared with the group at 41 weeks,both the group at 39 weeks(RR 0.71,95%CI 0.56-0.89)and the group at 40 weeks(RR 0.78,95%CI 0.65-0.92)had a lower risk of composite adverse neonatal outcomes.When Bishop score<4 points,there was no significant difference in the time to start labor,total labor time or time from induction to delivery among the three groups(P>0.05),when Bishop score≥4 points,the group induced at 39 weeks had a shorter time to start labor,total labor time and time from induction to delivery than the groups induced at 40 weeks and 41 weeks(P<0.05).Conclusions:Induction at 39 weeks of gestation may reduce some adverse outcomes for mothers and newborns without increasing the cesarean section rate.