OBJECTIVES: To assess the patterns and factors associated with prescription of FDA classified C, D and X category drugs (unsafe medications) during pregnancy.    METHODS: Cross-sectional analysis was conducted of pregnant women aged 20 and 49 years using data from the Medical Expenditure Panel Survey (MEPS) for the years 2009 and 2011.  Difference in the demographic variables, socioeconomic status, access to health care, and chronic conditions were tested for the use of safe medications.  All analyses accounted for the complex survey design of MEPS.  RESULTS: The study sample consisted of 1603 pregnant women (whites [595(58.8%)], married [924 (66.3%)], employed [918 (64.5%)], no chronic illness [1103 (65%)]).  A total of 413 (28.3%) women utilized medication of FDA category CDX.  The use of the category C medications was highest [337 (23.4%)] drugs followed by category D [101 (6.9 %)], and category X [64 (4.4)].  Women with chronic illness [adjusted Odds Ratio (aOR) = 1.61; 95% CI = 1.03, 2.52, P < 0.001], having fair or poor perceived health status (aOR = 1.95; 95% CI= 1.15, 3.31, P < 0.05), doing regular physical activity (aOR = 1.50; 95% CI= 1.12, 2.01, P < 0.01) were more likely to receive unsafe medication, while pregnant women with less than higher secondary education (OR = 0.30; 95% CI = 0.11, 0.81, P < 0.05),  with near poor (aOR: 0.53, 95% CI: 0.31,0.91, P<0.05) or middle income (aOR: 0.62, 95% CI: 0.40,0.95, P < 0.05), were less likely to receive unsafe medications. There were no differences rates of unsafe medications use by age, race, marital status, employment status, mental health, and smoking status. CONCLUSIONS: Nearly one-third of all pregnant women used FDA category CDX drugs.  Interventions should be carried out to reduce utilization of FDA CDX especially among the women with chronic conditions and poor health status.