Rozenberg P
Unité de recherche EA 7285, département d'obstétrique et gynécologie, université Versailles-Saint-Quentin, hôpital Poissy-Saint Germain, 78303 Poissy, France.
Gynecol Obstet Fertil Senol. 2018 May;46(5):481-488. doi: 10.1016/j.gofs.2018.03.009. Epub 2018 Apr 12.
The goal of induction of labor is to achieve vaginal delivery when the benefits of expeditious delivery outweigh the risks of continuing the pregnancy. In order to correctly understand the problematic of the elective induction of labor at 39 weeks of gestation (WG), two questions must be raised. (i) What is the perinatal mortality evolution according the gestational age at delivery? All the most recent and methodologically well-conducted studies are convergent: they show that the fetal mortality risk exceeds the perinatal/infant (during the first year of life) mortality risk from 39 WG. The benefit/risk balance related to the expectant management is therefore reversed from 39 WG in favor of the elective induction of labor when the considered issue is the perinatal mortality. (ii) What are the associated risks with elective induction of labor? While some observational studies suggested that the elective induction of labor after 37 WG was associated with an increased risk of cesarean sections, these studies presented a major methodological bias: an error in the control group selection. Indeed, the control group consisted of women in spontaneous labor, whereas the appropriate comparison group must be an expectant management group. Several large cohort studies using a rigorous methodology have shown that elective induction of labor at 39 WG reduces the cesarean section risk compared to an expectant management. Three systematic reviews with meta-analysis of randomized controlled trials comparing induction of labor with expectant management were published: two showed that the cesarean section risk was lowered with the induction of labor compared to an expectant management and the third that the cesarean section rates were similar. Finally, the most recent randomized controlled trial, published in 2016, showed no significant difference between the 2 arms in the cesarean section rate. In all, the most recent literature data, free from comparative bias, show that elective induction of labor at term is associated with a significant reduction in the cesarean section risk and perinatal morbidity and mortality compared to an expectant management.
引产的目的是在快速分娩的益处超过继续妊娠的风险时实现阴道分娩。为了正确理解妊娠39周（WG）时选择性引产的问题，必须提出两个问题。（i）根据分娩时的孕周，围产期死亡率如何变化？所有最新且方法学上进行良好的研究都一致表明：从妊娠39周起，胎儿死亡风险超过围产期/婴儿（出生后第一年）死亡风险。因此，当考虑的问题是围产期死亡率时，从妊娠39周起，与期待管理相关的利弊平衡就发生了逆转，有利于选择性引产。（ii）选择性引产的相关风险有哪些？虽然一些观察性研究表明，妊娠37周后选择性引产与剖宫产风险增加有关，但这些研究存在一个主要的方法学偏差：对照组选择错误。实际上，对照组由自然分娩的女性组成，而合适的比较组应该是期待管理组。几项采用严格方法的大型队列研究表明，与期待管理相比，妊娠39周时选择性引产可降低剖宫产风险。发表了三项对比较引产与期待管理的随机对照试验进行荟萃分析的系统评价：两项表明与期待管理相比，引产可降低剖宫产风险，第三项表明剖宫产率相似。最后，2016年发表的最新随机对照试验表明，两组的剖宫产率没有显著差异。总体而言，最新的无比较偏差的文献数据表明，与期待管理相比，足月选择性引产与剖宫产风险、围产期发病率和死亡率的显著降低相关。
