This article provides a comprehensive review of the published literature on the impact of expanding Medicaid for pregnant women to higher income groups of women. The major expansions took place between April 1987 and July 1989. These studies show evidence that new groups of pregnant women received health insurance coverage through Medicaid, and that some women received improved prenatal care services. The evidence is much weaker that the expansions led to improved birth outcomes. The fact that other parts of the developed world have experienced sustained declines in infant mortality without expansions of health insurance coverage points to the complexity in the origins of poor birth outcomes. It is possible that the benefits from the Medicaid expansions were merely victories in small battles within a much larger war that remains to be won.