Impact of labor induction at 39 weeks gestation compared with expectant management on maternal and perinatal morbidity among a cohort of low-risk women

To determine maternal and perinatal outcomes after induction of labor (IOL) at 39 weeks compared with expectant management. This is a retrospective national cohort study from the National Center for Health Statistics birth database. The study included singleton, low-risk pregnancies with a non-anomalous fetus delivered at 39–42 weeks gestation between 2015 and 2018. Maternal outcomes available included chorioamnionitis (Triple I), blood transfusion, intensive care unit (ICU) admission, uterine rupture, cesarean delivery (CD), and cesarean hysterectomy. Fetal and infant outcomes included stillbirth, 5-min Apgar ≤3, prolonged ventilation, seizures, ICU admission, and death within 28 days. We compared women undergoing IOL at 39 weeks to those managed expectantly. Non-adjusted and adjusted relative risks (aRRs) were estimated using multivariate log-binomial regression analysis. There were 15,900,956 births available for review of which 5,017,524 met inclusion and exclusion criteria. For the maternal outcomes, the IOL group was less likely to require a CD (aRR 0.880; 95% CI [0.874–0.886]; p value p value p value p value p value p value p value p value 0.011) or death (aRR 1.070; 95% CI [0.722–1.586]; p value 0.660). IOL at 39 weeks of gestation in a low-risk cohort is associated with a lower risk of CD and maternal infection, stillbirth, and lower neonatal morbidity. There was no effect on the risk for neonatal seizures or death.本研究旨在对比妊娠39周时引产（induction of labor, IOL）与期待治疗后的孕产妇及围产儿结局。本研究为一项基于美国国家卫生统计中心（National Center for Health Statistics, NCHS）出生登记数据库的回顾性全国队列研究，纳入2015至2018年间妊娠39~42周分娩、单胎、低风险且胎儿无结构异常的妊娠病例。本次研究关注的孕产妇结局指标包括绒毛膜羊膜炎（Triple I）、输血、重症监护病房（intensive care unit, ICU）入住、子宫破裂、剖宫产（cesarean delivery, CD）以及剖宫产子宫切除术；胎儿及新生儿结局指标包括死产、5分钟Apgar评分≤3、机械通气时间延长、惊厥、ICU入住以及产后28天内死亡。本研究将妊娠39周接受引产的孕妇与接受期待治疗的孕妇作为两组进行对比，采用多因素对数二项回归分析，估算未校正相对风险与校正相对风险（adjusted relative risks, aRRs）。本次研究共计获取15,900,956条分娩记录用于审查，其中5,017,524条符合纳入与排除标准。针对孕产妇结局，引产组剖宫产（aRR 0.880；95%置信区间[0.874~0.886]；P=0.011）及孕产妇死亡（aRR 1.070；95%置信区间[0.722~1.586]；P=0.660）的发生风险更低。在低风险妊娠队列中，妊娠39周引产与更低的剖宫产、孕产妇感染、死产风险及新生儿发病率相关，且对新生儿惊厥及新生儿死亡风险无显著影响。