Chronic hypertension, cigarette smoking, and abruptio placentae.

We investigated the importance of maternal hypertension and cigarette smoking, and their interaction, as risk factors for abruptio placentae, using Massachusetts birth certificate data for 1987-1988. We used multiple logistic regression procedures to model data from 943 abruptio placentae cases and 10,648 randomly selected births. Risk of abruption was associated with a history of chronic hypertension (adjusted OR = 2.3, 95% CI: 1.5-3.5) and cigarette smoking during pregnancy (adjusted OR = 1.7, 95% CI: 1.5-2.0). There was also evidence of interaction between chronic hypertension and cigarette smoking. The hypoxemia that results from exposure to cigarette smoke and the alterations in uterine blood flow that result from hypertension may lead to placental lesions that cause abruption.