Department of Neuroscience, Reproductive Sciences and Dentistry, School of Medicine, University of Naples Federico II, Naples, Italy.
Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Sidney Kimmel Medical College of Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
Acta Obstet Gynecol Scand. 2019 Aug;98(8):958-966. doi: 10.1111/aogs.13561. Epub 2019 Mar 6.
The lowest incidence of perinatal morbidity and mortality occurs around 39-40 weeks. Therefore, some have advocated induction of uncomplicated singleton gestations once they reach full-term. The aim of the study was to evaluate the risk of cesarean delivery, and any maternal and perinatal effects of a policy of induction of labor in women with full-term uncomplicated singleton gestations.
We performed an electronic search from inception of each database to August 2018. All results were then limited to randomized trial. No restrictions for language or geographic location were applied. Inclusion criteria were randomized clinical trials of asymptomatic women with uncomplicated, singleton gestations at full-term (ie, between 39 and 40 weeks) who were randomized to either planned induction of labor or control (ie, expectant management). Only trials on asymptomatic singleton gestations without premature rupture of membranes or any other indications for induction evaluating the effectiveness of planned induction of labor in full-term singleton gestations were included. The primary outcome was the incidence of cesarean delivery.
Seven randomized clinical trials, including 7598 participants were analyzed. Three studies enrolled only women with favorable cervix, defined as a Bishop score of ≥5 in nulliparous women or ≥4 in multiparous women. One trial included only women aged 35 years or older. Women randomized to the planned induction of labor, received scheduled induction usually at 39 to 39 weeks of gestation, whereas women in the control group received expectant management usually until 41-42 weeks of gestation, or earlier if medically indicated. Methods of induction usually included cervical ripening, with either misoprostol or Foley catheter, in conjunction with or followed by oxytocin for women with unfavorable cervix, and oxytocin and artificial rupture of membranes for those with favorable cervix. Five trials also used artificial rupture of membranes as a method for induction. Uncomplicated full-term singleton gestations that were randomized to receive induction of labor had similar incidence of cesarean delivery compared with controls (18.6% vs 21.4%; relative risk 0.96, 95% CI 0.78-1.19). Regarding neonatal outcomes, induction of labor at full-term was associated with a significantly lower rate of meconium-stained amniotic fluid (4.0% vs 13.5%; relative risk 0.32, 95% CI 0.18-0.57), and lower mean birthweight (mean difference -98.96 g, 95% CI -126.29 to -71.63) compared with the control group. There were no between-group differences in other adverse neonatal outcomes.
Induction of labor at about 39 weeks is not associated with increased risk of cesarean delivery.
围产期发病率和死亡率最低的时期发生在 39-40 周左右。因此，有人主张一旦达到足月，就对无并发症的单胎妊娠进行引产。本研究的目的是评估足月无并发症的单胎妊娠孕妇引产的剖宫产风险，以及任何母婴围生期影响。
我们从每个数据库的创建开始进行电子检索，直到 2018 年 8 月。然后，将所有结果都限制为随机试验。未对语言或地理位置施加任何限制。纳入标准为无症状的足月（即 39-40 周）、无并发症、单胎妊娠的妇女进行随机分组，分别接受计划性引产或对照组（即期待治疗）的随机临床试验。仅纳入关于无症状的单胎妊娠、胎膜未破裂或其他引产指征的随机临床试验，以评估足月单胎妊娠中计划性引产的有效性。主要结局为剖宫产率。
分析了 7 项随机临床试验，共纳入 7598 名参与者。3 项研究仅纳入宫颈条件良好的妇女，定义为初产妇的 Bishop 评分≥5 分，经产妇≥4 分。1 项试验仅纳入 35 岁或以上的妇女。接受计划性引产的妇女通常在 39 周至 39 周+6 天行计划性引产，而对照组的妇女接受期待治疗，通常在 41-42 周+6 天，或在医学指征下更早进行引产。诱导分娩的方法通常包括宫颈成熟，对宫颈条件不佳的妇女使用米索前列醇或 Foley 导管，联合或随后使用催产素，对宫颈条件良好的妇女使用催产素和人工破膜。5 项试验还使用人工破膜作为引产方法。与对照组相比，随机接受引产的足月无并发症的单胎妊娠的剖宫产率相似（18.6% vs 21.4%；相对风险 0.96，95%CI 0.78-1.19）。关于新生儿结局，足月引产与羊水粪染发生率显著降低相关（4.0% vs 13.5%；相对风险 0.32，95%CI 0.18-0.57），平均出生体重也显著降低（平均差值-98.96g，95%CI-126.29 至-71.63）。两组间其他不良新生儿结局无差异。
约 39 周行引产与剖宫产风险增加无关。
