Middleton Philippa, Shepherd Emily, Crowther Caroline A
Healthy Mothers, Babies and Children, South Australian Health and Medical Research Institute, Women's and Children's Hospital, 72 King William Road, Adelaide, South Australia, Australia, 5006.
Cochrane Database Syst Rev. 2018 May 9;5(5):CD004945. doi: 10.1002/14651858.CD004945.pub4.
Beyond term, the risks of stillbirth or neonatal death increase. It is unclear whether a policy of labour induction can reduce these risks. This Cochrane review is an update of a review that was originally published in 2006 and subsequently updated in 2012 OBJECTIVES: To assess the effects of a policy of labour induction at or beyond term compared with a policy of awaiting spontaneous labour or until an indication for birth induction of labour is identified) on pregnancy outcomes for infant and mother.
We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform (ICTRP) (9 October 2017), and reference lists of retrieved studies.
Randomised controlled trials (RCTs) conducted in pregnant women at or beyond term, comparing a policy of labour induction with a policy of awaiting spontaneous onset of labour (expectant management). We also included trials published in abstract form only. Cluster-RCTs, quasi-RCTs and trials using a cross-over design are not eligible for inclusion in this review.We included pregnant women at or beyond term. Since a risk factor at this stage of pregnancy would normally require an intervention, only trials including women at low risk for complications were eligible. We accepted the trialists' definition of 'low risk'. The trials of induction of labour in women with prelabour rupture of membranes at or beyond term were not considered in this review but are considered in a separate Cochrane review.
Two reviewers independently assessed trials for inclusion, assessed risk of bias and extracted data. Data were checked for accuracy. We assessed the quality of evidence using the GRADE approach.
In this updated review, we included 30 RCTs (reporting on 12,479 women). The trials took place in Norway, China, Thailand, the USA, Austria, Turkey, Canada, UK, India, Tunisia, Finland, Spain, Sweden and the Netherlands. They were generally at a moderate risk of bias.Compared with a policy of expectant management, a policy of labour induction was associated with fewer (all-cause) perinatal deaths (risk ratio (RR) 0.33, 95% confidence interval (CI) 0.14 to 0.78; 20 trials, 9960 infants; moderate-quality evidence). There were two perinatal deaths in the labour induction policy group compared with 16 perinatal deaths in the expectant management group. The number needed to treat to for an additional beneficial outcome (NNTB) with induction of labour in order to prevent one perinatal death was 426 (95% CI 338 to 1337). There were fewer stillbirths in the induction group (RR 0.33, 95% CI 0.11 to 0.96; 20 trials, 9960 infants; moderate-quality evidence); there was one stillbirth in the induction policy arm and 10 in the expectant management group.For women in the policy of induction arms of trials, there were fewer caesarean sections compared with expectant management (RR 0.92, 95% CI 0.85 to 0.99; 27 trials, 11,738 women; moderate-quality evidence); and a corresponding marginal increase in operative vaginal births with induction (RR 1.07, 95% CI 0.99 to 1.16; 18 trials, 9281 women; moderate-quality evidence). There was no evidence of a difference between groups for perineal trauma (RR 1.09, 95% CI 0.65 to 1.83; 4 trials; 3028 women; low-quality evidence), postpartum haemorrhage (RR 1.09 95% CI 0.92 to 1.30, 5 trials; 3315 women; low-quality evidence), or length of maternal hospital stay (average mean difference (MD) -0.34 days, 95% CI -1.00 to 0.33; 5 trials; 1146 women; Tau² = 0.49; I² 95%; very low-quality evidence).Rates of neonatal intensive care unit (NICU) admission were lower (RR 0.88, 95% CI 0.77 to 1.01; 13 trials, 8531 infants; moderate-quality evidence) and fewer babies had Apgar scores less than seven at five minutes in the induction groups compared with expectant management (RR 0.70, 95% CI 0.50 to 0.98; 16 trials, 9047 infants; moderate-quality evidence).There was no evidence of a difference for neonatal trauma (RR 1.18, 95% CI 0.68 to 2.05; 3 trials, 4255 infants; low-quality evidence), for induction compared with expectant management.Neonatal encephalopathy, neurodevelopment at childhood follow-up, breastfeeding at discharge and postnatal depression were not reported by any trials.In subgroup analyses, no clear differences between timing of induction (< 41 weeks versus ≥ 41 weeks' gestation) or by state of cervix were seen for perinatal death, stillbirth, NICU admission, caesarean section, or perineal trauma. However, operative vaginal birth was more common in the inductions at < 41 weeks' gestation subgroup compared with inductions at later gestational ages. The majority of trials (about 75% of participants) adopted a policy of induction at ≥ 41 weeks (> 287 days) gestation for the intervention arm.
AUTHORS' CONCLUSIONS: A policy of labour induction at or beyond term compared with expectant management is associated with fewer perinatal deaths and fewer caesarean sections; but more operative vaginal births. NICU admissions were lower and fewer babies had low Apgar scores with induction. No important differences were seen for most of the other maternal and infant outcomes.Most of the important outcomes assessed using GRADE had a rating of moderate or low-quality evidence - with downgrading decisions generally due to study limitations such as lack of blinding (a condition inherent in comparisons between a policy of acting and of waiting), or imprecise effect estimates. One outcome (length of maternal stay) was downgraded further to very low-quality evidence due to inconsistency.Although the absolute risk of perinatal death is small, it may be helpful to offer women appropriate counselling to help choose between scheduled induction for a post-term pregnancy or monitoring without (or later) induction).The optimal timing of offering induction of labour to women at or beyond term warrants further investigation, as does further exploration of risk profiles of women and their values and preferences. Individual participant meta-analysis is likely to help elucidate the role of factors, such as parity, in influencing outcomes of induction compared with expectant management.
超过预产期后，死产或新生儿死亡风险增加。引产政策是否能降低这些风险尚不清楚。本Cochrane系统评价是对2006年首次发表并于2012年更新的系统评价的更新。
评估与等待自然分娩或直到确定引产指征的政策相比，在预产期及以后进行引产政策对母婴妊娠结局的影响。
我们检索了Cochrane妊娠与分娩试验注册库、ClinicalTrials.gov和世界卫生组织国际临床试验注册平台（ICTRP）（2017年10月9日），并检索了检索到的研究的参考文献列表。
在预产期及以后的孕妇中进行的随机对照试验（RCT），比较引产政策与等待自然分娩开始（期待管理）的政策。我们还纳入了仅以摘要形式发表的试验。整群RCT、半随机RCT和采用交叉设计的试验不符合本系统评价的纳入标准。我们纳入了预产期及以后的孕妇。由于妊娠此阶段的风险因素通常需要干预，因此仅纳入了包括并发症低风险女性的试验。我们接受试验者对“低风险”的定义。本系统评价未考虑预产期及以后胎膜早破女性引产的试验，但在另一项Cochrane系统评价中进行了考虑。
两名评价员独立评估试验是否纳入，评估偏倚风险并提取数据。检查数据的准确性。我们使用GRADE方法评估证据质量。
在本次更新的系统评价中，我们纳入了30项RCT（涉及12479名女性）。试验在挪威、中国、泰国、美国、奥地利、土耳其、加拿大、英国、印度、突尼斯、芬兰、西班牙、瑞典和荷兰进行。它们的偏倚风险一般为中度。与期待管理政策相比，引产政策导致的（全因）围产期死亡更少（风险比（RR）0.33，95%置信区间（CI）0.14至0.78；20项试验，9960名婴儿；中等质量证据）。引产政策组有2例围产期死亡，而期待管理组有16例围产期死亡。为预防1例围产期死亡，引产以获得额外有益结局所需治疗的人数（NNTB）为426（95%CI 338至1337）。引产组的死产更少（RR 0.33，95%CI 0.11至0.96；20项试验，9960名婴儿；中等质量证据）；引产政策组有1例死产，期待管理组有10例。与期待管理相比，试验引产组的女性剖宫产更少（RR 0.92，95%CI 0.85至0.99；27项试验，11738名女性；中等质量证据）；引产导致的手术阴道分娩相应略有增加（RR 1.07，95%CI 0.99至1.16；18项试验，9281名女性；中等质量证据）。两组在会阴创伤方面无差异证据（RR 1.09，95%CI 0.65至1.83；4项试验；3028名女性；低质量证据），产后出血方面也无差异证据（RR 1.09，95%CI 0.92至1.30，5项试验；3315名女性；低质量证据），或产妇住院时间方面也无差异证据（平均差值（MD）-0.34天，95%CI -1.00至0.33；5项试验；1146名女性；Tau² = 0.49；I² 95%；极低质量证据）。新生儿重症监护病房（NICU）入院率更低（RR 0.88，95%CI 0.77至1.01；13项试验，8531名婴儿；中等质量证据）；与期待管理相比，引产组5分钟时Apgar评分低于7分的婴儿更少（RR 0.70，95%CI 0.50至0.98；16项试验，9047名婴儿；中等质量证据）。与期待管理相比，引产在新生儿创伤方面无差异证据（RR 1.18，95%CI 0.68至2.05；3项试验，4255名婴儿；低质量证据）。任何试验均未报告新生儿脑病、儿童随访时的神经发育、出院时的母乳喂养及产后抑郁情况。在亚组分析中，围产期死亡、死产、NICU入院、剖宫产或会阴创伤方面，引产时间（<41周与≥41周妊娠）或宫颈状态之间未发现明显差异。然而，与孕周较大时的引产相比，<41周妊娠亚组的引产手术阴道分娩更为常见。大多数试验（约75%的参与者）对干预组采用≥41周（>287天）妊娠引产政策。
与期待管理相比，预产期及以后的引产政策与更少的围产期死亡和更少的剖宫产相关；但手术阴道分娩更多。引产时NICU入院率更低，Apgar评分低的婴儿更少。大多数其他母婴结局未发现重要差异。使用GRADE评估的大多数重要结局的证据质量为中等或低质量——降级决定通常是由于研究局限性，如缺乏盲法（行动政策与等待政策比较中固有的情况）或效应估计不精确。一项结局（产妇住院时间）因不一致性进一步降级为极低质量证据。尽管围产期死亡的绝对风险很小，但为女性提供适当咨询以帮助她们在晚期妊娠计划引产或不引产（或稍后引产）进行监测之间做出选择可能会有所帮助。为预产期及以后的女性提供引产的最佳时机值得进一步研究，对女性的风险特征及其价值观和偏好进行进一步探索也值得研究。个体参与者荟萃分析可能有助于阐明诸如产次等因素在影响引产与期待管理结局方面的作用。
