Department of Obstetrics and Gynaecology, University of Melbourne, Melbourne, Victoria, Australia.
Mercy Perinatal, Mercy Hospital for Women, 163 Studley Rd., Heidelberg, Victoria, 3084, Australia.
BMC Med. 2021 May 25;19(1):126. doi: 10.1186/s12916-021-01988-5.
Post-term gestation beyond 41 completed weeks of gestation is known to be associated with a sharp increase in the risk of stillbirth and perinatal mortality. However, the risk of common adverse outcomes related to labour, such as shoulder dystocia and post-partum haemorrhage for those delivering at this advanced gestation, remains poorly characterised. The objective of this study was to examine the risk of adverse, labour-related outcomes for women progressing to 42 weeks gestation or beyond, compared with those giving birth at 39 completed weeks.
We performed a state-wide cohort study using routinely collected perinatal data in Australia. Comparing the two gestation cohorts, we examined the adjusted relative risk of clinically significant labour-related adverse outcomes, including macrosomia (≥ 4500 at birth), post-partum haemorrhage (≥1000 ml), shoulder dystocia, 3rd or 4th degree perineal tear and unplanned caesarean section. Parity, maternal age and mode of birth were adjusted for using logistic regression.
The study cohort included 91,314 women who birthed at 39 completed weeks and 4317 at ≥42 completed weeks. Compared to 39 weeks gestation, those giving birth ≥42 weeks gestation had an adjusted relative risk (aRR) of 1.85 (95% CI 1.55-2.20) for post-partum haemorrhage following vaginal birth, 2.29 (95% CI 1.89-2.78) following instrumental birth and 1.44 (95% CI 1.17-1.78) following emergency caesarean section; 1.43 (95% CI 1.16-1.77) for shoulder dystocia (for non-macrosomic babies); and 1.22 (95% CI 1.03-1.45) for 3rd or 4th degree perineal tear (all women). The adjusted relative risk of giving birth to a macrosomic baby was 10.19 (95% CI 8.26-12.57) among nulliparous women and 4.71 (95% CI 3.90-5.68) among multiparous women. The risk of unplanned caesarean section was 1.96 (95% CI 1.86-2.06) following any labour and 1.47 (95% CI 1.38-1.56) following induction of labour.
Giving birth at ≥42 weeks gestation may be an under-recognised risk factor for several important, labour-related adverse outcomes. Clinicians should be aware that labour at this advanced gestation incurs a higher risk of adverse outcomes. In addition to known perinatal risks, the risk of obstetric complications should be considered in the counselling of women labouring at post-term gestation.
超过 41 周的过期妊娠与死产和围产儿死亡率急剧增加有关。然而，对于在这个晚期分娩的人来说，与分娩相关的常见不良结局的风险，如肩难产和产后出血，仍未得到很好的描述。本研究的目的是检查进展到 42 周或以上的孕妇与 39 周足月分娩的孕妇相比，与劳动相关的不良结局的风险。
我们使用澳大利亚常规收集的围产期数据进行了一项全州范围的队列研究。在比较两个妊娠队列时，我们检查了有临床意义的与劳动相关的不良结局的调整相对风险，包括巨大儿（出生时体重≥4500 克）、产后出血（≥1000 毫升）、肩难产、三度或四度会阴撕裂和计划外剖宫产。使用逻辑回归调整了产次、产妇年龄和分娩方式。
研究队列包括 91314 名在 39 周足月分娩的妇女和 4317 名≥42 周足月分娩的妇女。与 39 周妊娠相比，≥42 周妊娠的妇女阴道分娩后产后出血的调整相对风险（aRR）为 1.85（95%CI 1.55-2.20），器械分娩后为 2.29（95%CI 1.89-2.78），紧急剖宫产后为 1.44（95%CI 1.17-1.78）；肩难产的调整相对风险为 1.43（95%CI 1.16-1.77）（对于非巨大儿婴儿）；会阴三度或四度撕裂的调整相对风险为 1.22（95%CI 1.03-1.45）（所有妇女）。初产妇分娩巨大儿的调整相对风险为 10.19（95%CI 8.26-12.57），多产妇为 4.71（95%CI 3.90-5.68）。任何分娩后的无计划剖宫产风险为 1.96（95%CI 1.86-2.06），引产后的风险为 1.47（95%CI 1.38-1.56）。
在≥42 周时分娩可能是几个重要的与劳动相关的不良结局的一个被低估的危险因素。临床医生应该意识到，在这个晚期分娩会增加不良结局的风险。除了已知的围产期风险外，在对过期妊娠的妇女进行咨询时，还应考虑产科并发症的风险。
