PURPOSE: To provide information on the prevalence of use of cardiovascular drugs, some of which may have fetotoxic or teratogenic effects, in the outpatient setting among pregnant women in the United States. METHODS: A retrospective study was conducted using the automated databases of seven health plans participating in the HMO Research Network Center for Education and Research on Therapeutics (CERT). Women who delivered an infant from 1 January 2001 to 31 December 2005 were identified. Cardiovascular drug use was evaluated assuming a gestational duration of 270 days. RESULTS: During the period 2001 through 2005, 118,935 deliveries were identified that met the criteria for study; 3.1% of women (N = 3672) were dispensed an antihypertensive medication and 0.12% of women (N = 146) were dispensed an antihyperlipidemic medication at any time during pregnancy. The most common antihypertensive drugs dispensed during pregnancy were nifedipine (1219 deliveries; 1.0%), methyldopa (961 deliveries; 0.8%), atenolol (593 deliveries; 0.5%), and labetalol (576 deliveries; 0.5%). Overall, 134 women (0.11%) received an angiotensin converting enzyme (ACE) inhibitor and 7 women (0.006%) received an angiotensin II receptor blocker (ARB) during pregnancy. Statins were the most commonly dispensed antihyperlipidemic drugs (71 deliveries; 0.06%). CONCLUSIONS: The prevalence of use of cardiovascular drugs that are suspected to be fetotoxic or teratogenic (ACE inhibitors, ARBs, and statins) was low in this cohort of pregnant women. Differing patterns of use across health plans suggests that further research is needed to evaluate the potential differential effects of cardiovascular drugs to assist prescribers and patients in making informed treatment decisions.