Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden.
BJOG. 2014 Jan;121(2):224-9. doi: 10.1111/1471-0528.12444. Epub 2013 Sep 16.
To evaluate whether women with a caesarean section at their first delivery have an increased risk of retained placenta at their second delivery.
Population-based cohort study.
Sweden.
All women with their first and second singleton deliveries in Sweden during the years 1994-2006 (n = 258,608). Women with caesarean section or placental abruption in their second pregnancy were not included in the study population.
The risk of retained placenta at second delivery was estimated for women with a first delivery by caesarean section (n = 19,458), using women with a first vaginal delivery as reference (n = 239,150). Risks were calculated as odds ratios by unconditional logistic regression analysis with 95% confidence intervals (95%) after adjustments for maternal, delivery, and infant characteristics.
Retained placenta with normal (≤1000 ml) and heavy (>1000 ml) bleeding.
The overall rate of retained placenta was 2.07%. In women with a previous caesarean section and in women with previous vaginal delivery, the corresponding rates were 3.44% and 1.96%, respectively. Compared with women with a previous vaginal delivery, women with a previous caesarean section had an increased risk of retained placenta (adjusted OR 1.45; 95% CI 1.32-1.59), and the association was more pronounced for retained placenta with heavy bleeding (adjusted OR 1.61; 95% CI 1.44-1.79).
Our report shows an increased risk for retained placenta in women previously delivered by caesarean section, a finding that should be considered in discussions of mode of delivery.
评估首次剖宫产分娩的女性在第二次分娩时是否有发生胎盘滞留的风险增加。
基于人群的队列研究。
瑞典。
1994 年至 2006 年期间在瑞典首次分娩且为单胎的所有女性（n=258608）。未将第二次妊娠行剖宫产术或胎盘早剥的女性纳入研究人群。
通过对 19458 例首次剖宫产分娩的女性（n=19458）和 239150 例首次阴道分娩的女性（n=239150）进行分析，评估首次经剖宫产分娩的女性在第二次分娩时发生胎盘滞留的风险。采用非条件 logistic 回归分析计算风险比（OR）及其 95%置信区间（95%CI），校正了母亲、分娩和婴儿特征后进行分析。
正常（≤1000ml）和大量（>1000ml）出血的胎盘滞留。
胎盘滞留的总体发生率为 2.07%。在有前置剖宫产史和有前置阴道分娩史的女性中，相应的发生率分别为 3.44%和 1.96%。与有前置阴道分娩史的女性相比，有前置剖宫产史的女性发生胎盘滞留的风险增加（校正 OR 1.45；95%CI 1.32-1.59），且大量出血性胎盘滞留的风险更为明显（校正 OR 1.61；95%CI 1.44-1.79）。
本报告显示，有剖宫产史的女性发生胎盘滞留的风险增加，这一发现应在讨论分娩方式时予以考虑。
