Ananth C V, Savitz D A, Luther E R
Department of Epidemiology, School of Public Health, University of North Carolina at Chapel Hill, USA.
Am J Epidemiol. 1996 Nov 1;144(9):881-9. doi: 10.1093/oxfordjournals.aje.a009022.
The authors carried out an epidemiologic study to evaluate the role of maternal cigarette smoking as a potential risk factor for placental abruption, placenta previa, and uterine bleeding of unknown etiology in pregnancy. Data for this prospective cohort study were obtained from women seeking prenatal care at any of the two tertiary, seven regional, or 17 community hospitals in the province of Nova Scotia, Canada, between January 1, 1986, and December 31, 1993. A total of 87,184 pregnancies (among 61,667 women) were registered in the database. Women who smoked during pregnancy (33%) were compared with nonsmokers, and all women were followed until the termination of pregnancy. Placental abruption was indicated in 9.9 per 1,000 pregnancies, while placenta previa and uterine bleeding of unknown etiology were indicated in 3.6 and 58.9 per 1,000 pregnancies, respectively. Women who smoked had a twofold increase in the risk of abruption (relative risk = 2.05, 95% confidence interval (CI) 1.75-2.40) in comparison with nonsmokers, while the relative risk for placenta previa was 1.36 (95% CI 1.04-1.79). However, cigarette smoking was not found to be associated with uterine bleeding of unknown etiology (relative risk = 1.01, 95% CI 0.94-1.08). There was no evidence for an increased risk of uteroplacental bleeding disorders with increasing numbers of cigarettes smoked. All analyses were adjusted for potentially confounding factors through logistic regression models based on the method of generalized estimating equations. The study confirms a positive association between cigarette smoking and placental abruption and a weak association with placenta previa but not with other uterine bleeding. The distinct pattern of results for placental abruption, placenta previa, and uterine bleeding of unknown origin suggests that these three uteroplacental bleeding disorders do not have a common etiology in relation to cigarette smoking.
作者开展了一项流行病学研究，以评估孕妇吸烟作为胎盘早剥、前置胎盘和孕期不明原因子宫出血潜在危险因素的作用。这项前瞻性队列研究的数据来自1986年1月1日至1993年12月31日期间在加拿大新斯科舍省的两家三级医院、七家地区医院或17家社区医院中任何一家寻求产前护理的妇女。数据库中共登记了87184例妊娠（涉及61667名妇女）。将孕期吸烟的妇女（33%）与不吸烟者进行比较，所有妇女均随访至妊娠结束。每1000例妊娠中胎盘早剥的发生率为9.9例，而前置胎盘和不明原因子宫出血的发生率分别为每1000例妊娠3.6例和58.9例。与不吸烟者相比，吸烟妇女发生胎盘早剥的风险增加了两倍（相对风险=2.05，95%置信区间[CI]1.75 - 2.40），而前置胎盘的相对风险为1.36（95%CI 1.04 - 1.79）。然而，未发现吸烟与不明原因子宫出血有关（相对风险=1.01，95%CI 0.94 - 1.08）。没有证据表明随着吸烟量增加，子宫胎盘出血性疾病的风险会增加。所有分析均通过基于广义估计方程方法的逻辑回归模型对潜在混杂因素进行了校正。该研究证实吸烟与胎盘早剥之间存在正相关，与前置胎盘存在弱相关，但与其他子宫出血无关。胎盘早剥、前置胎盘和不明原因子宫出血的不同结果模式表明，这三种子宫胎盘出血性疾病在与吸烟相关的病因方面没有共同之处。
