OBJECTIVE: To estimate the incidence of maternal cardiovascular and pulmonary events and the prevalence of other comorbid conditions among pregnant smokers. METHODS: We queried the Nationwide Inpatient Sample (NIS) from the Healthcare Cost and Utilization Project (HCUP) of the Agency for Healthcare Research and Quality (AHRQ) for pregnancy-related discharge codes for the years 2000-2004. The prevalence of various conditions and the incidence of various complications were compared between smokers and nonsmokers. RESULTS: The majority of smokers were young and white and had public insurance. Smokers were more likely to have experienced deep vein thrombosis (odds ratio [OR] 1.3, 95% confidence interval [CI] 1.1, 1.6), stroke (OR 1.7, 95% CI 1.2, 2.5), pulmonary embolus (OR 2.5, 95% CI 2.1, 3.0), and myocardial infarction (OR 4.6, 95% CI 3.3, 6.4). They were 3 times more likely to have experienced influenza or pneumonia (OR 2.9, 95% CI 2.7, 3.2) and 15 times more likely to have bronchitis (OR 15.2, 95% CI 12.8, 18.2). They were more likely to suffer from a number of comorbidities, including asthma (OR 4.0, 95% CI 3.7, 4.2) and gastrointestinal ulcers (OR 3.7, 95% CI 2.6, 5.5). Although they were less likely to have experienced gestational diabetes (OR 0.9, 95% CI 0.9, 1.0), preeclampsia (OR 0.8, 95% CI 0.8, 0.9), or eclampsia (OR 0.7, 95% CI 0.6, 0.9), they were more than 5 times as likely to have experienced an ectopic pregnancy (OR 5.4, 95% CI 4.6, 6.3). CONCLUSIONS: Smoking has a negative impact on maternal health. Counseling about the risks of smoking in pregnancy should include not only fetal risks but maternal risks as well.