Department of Obstetrics and Gynecology, NYU Winthrop Hospital, NYU Long Island School of Medicine, Mineola, NY.
Department of Obstetrics and Gynecology, Christiana Care Hospital, Delaware, DE.
Am J Obstet Gynecol. 2019 Jul;221(1):61.e1-61.e7. doi: 10.1016/j.ajog.2019.02.036. Epub 2019 Feb 22.
Prior studies have reported an increased risk for preterm delivery following a term cesarean delivery. However, these studies did not adjust for high-risk conditions related to the first cesarean delivery and are known to recur.
The objective of the study was to determine whether there is an association between term cesarean delivery in the first pregnancy and subsequent spontaneous or indicated preterm delivery.
This was a retrospective cohort study of women with the first 2 consecutive singleton deliveries (2007-2014) identified through a linked pregnancy database at a single institution. Women with a first pregnancy that resulted in cesarean delivery at term were compared with women whose first pregnancy resulted in a vaginal delivery at term. Exclusion criteria were known to recur medical or obstetrical complications during the first pregnancy. A propensity score analysis was performed by matching women who underwent a cesarean delivery with those who underwent a vaginal delivery in the first pregnancy. The association between cesarean delivery in the first pregnancy and preterm delivery in the second pregnancy in this matched set was examined using conditional logistic regression. The primary outcome was overall preterm delivery <37 weeks in the second pregnancy. Secondary outcomes included type of preterm delivery (spontaneous vs indicated), late preterm delivery (34-36 6/7 weeks), early preterm delivery (<34 weeks), and small-for-gestational-age birth.
Of a total of 6456 linked pregnancies, 2284 deliveries were matched; 1142 were preceded by cesarean delivery and 1142 were preceded by vaginal delivery. The main indications for cesarean delivery in the first pregnancy were dystocia in 703 (61.5%), nonreassuring fetal status in 222 (19.4%), breech presentation in 100 (8.8%), and other in 84 (7.4%). The mean (SD) gestational ages at delivery for the second pregnancy was 38.8 (1.8) and 38.9 (1.7) weeks, respectively, for prior cesarean delivery and vaginal delivery. The risks of preterm delivery in the second pregnancy among women with a previous cesarean and vaginal delivery were 6.0% and 5.2%, respectively (adjusted odds ratio, 1.46, 95% confidence interval, [CI] 0.77-2.76). In an analysis stratified by the type of preterm delivery in the second pregnancy, no associations were seen between cesarean delivery in the first pregnancy and spontaneous preterm delivery (4.6% vs 3.9%; adjusted odds ratio, 1.40, 95% confidence interval, 0.59-3.32) or indicated preterm delivery (1.6% vs 1.4%; adjusted odds ratio, 1.21, 95% confidence interval, 0.60-2.46). Similarly, no significant differences were found in late preterm delivery (4.6% vs 4.1%; adjusted odds ratio, 1.13, 95% confidence interval, 0.55-2.29), early preterm delivery (1.6% vs 1.2%; adjusted odds ratio, 1.25, 95% confidence interval, 0.59-2.67), or neonates with birthweight less than the fifth percentile for gestational age (3.6% vs 2.2%; adjusted odds ratio, 1.26, 95% confidence interval, 0.52-3.06).
After robust adjustment for confounders through a propensity score analysis related to the indication for the first cesarean delivery at term, cesarean delivery is not associated with an increase in preterm delivery, spontaneous or indicated, in the subsequent pregnancy.
先前的研究报告称，足月剖宫产会增加早产的风险。然而，这些研究并未调整与首次剖宫产相关的高危情况，而这些高危情况已知会再次出现。
本研究旨在确定首次足月剖宫产与随后自发性或指征性早产之间是否存在关联。
这是一项回顾性队列研究，纳入了一家机构通过妊娠数据库链接的首次连续两次单胎妊娠（2007-2014 年）的女性。将首次妊娠行择期剖宫产的女性与首次妊娠行阴道分娩的女性进行比较。排除标准为首次妊娠期间已知存在复发的医学或产科并发症。通过匹配首次行剖宫产和阴道分娩的女性进行倾向评分分析。在匹配组中，使用条件逻辑回归检查首次妊娠行剖宫产与第二次妊娠早产之间的关联。主要结局为第二次妊娠＜37 周的总体早产。次要结局包括早产类型（自发性早产与指征性早产）、晚期早产（34-36 6/7 周）、早期早产（＜34 周）和小于胎龄儿出生。
在总共 6456 个链接的妊娠中，有 2284 个分娩被匹配；1142 个妊娠前进行了剖宫产，1142 个妊娠前进行了阴道分娩。首次剖宫产的主要指征为产程困难 703 例（61.5%）、胎儿情况不乐观 222 例（19.4%）、臀位 100 例（8.8%）和其他情况 84 例（7.4%）。第二次妊娠的平均（SD）分娩孕周分别为首次剖宫产和阴道分娩后的 38.8（1.8）和 38.9（1.7）周。有过剖宫产和阴道分娩史的女性中，第二次妊娠早产的风险分别为 6.0%和 5.2%（调整后的优势比，1.46，95%置信区间 [CI]，0.77-2.76）。在按第二次妊娠早产类型分层的分析中，首次剖宫产与自发性早产（4.6% vs 3.9%；调整后的优势比，1.40，95%置信区间，0.59-3.32）或指征性早产（1.6% vs 1.4%；调整后的优势比，1.21，95%置信区间，0.60-2.46）之间均未见关联。同样，晚发性早产（4.6% vs 4.1%；调整后的优势比，1.13，95%置信区间，0.55-2.29）、早期早产（1.6% vs 1.2%；调整后的优势比，1.25，95%置信区间，0.59-2.67）或出生体重低于胎龄第 5 百分位的新生儿（3.6% vs 2.2%；调整后的优势比，1.26，95%置信区间，0.52-3.06）之间也未发现显著差异。
通过与首次足月剖宫产指征相关的倾向评分分析对混杂因素进行稳健调整后，剖宫产与随后妊娠的自发性或指征性早产增加无关。
