Using linked birth and death certificates for participants served by a Healthy Start program in South Carolina and community controls, we found that the Healthy Start program contributed to significant improvements in prenatal care, breastfeeding initiation, and participation in the Special Supplemental Nutrition Program for Women, Infants, and Children and significant reductions in inadequate weight gain and large-for-gestational-age births. However, Healthy Start participants were more likely to gain excessive weight during pregnancy, and there were no significant differences in perinatal outcomes. (Am J Public Health. Published online ahead of print March 9, 2023:e1–e5. https://doi.org/10.2105/AJPH.2023.307232 )