This paper documents the changing picture of health insurance coverage for pregnant women in the four-year period following Medicaid expansion and assesses the extent to which the crowding-out phenomenon may have influenced the observed trends. The report documents the distribution of insurance coverage for pregnant women in the post-expansion period and describes demographic characteristics of women covered under Medicaid. It examines the rate at which Medicaid-eligible women enroll in the program and addresses the crowding-out issue by comparing the trend in employer-sponsored coverage among poor and near-poor pregnant women with those among nonpregnant women and men of similar ages and incomes.