Birth certificate data, collected for every birth in the United States, are frequently used for public health research. Such data have been used to track progress toward the Healthy People 2020 maternal and child health goals and to analyze socioeconomic disparities in health outcomes. A new Standard Certificate of Live Birth was issued in 2003, and all states had adopted the new form by 2015. This brief presents data on the reliability of some data collected using the new birth certificate form, particularly variables critical for studying disparities in maternal and child health outcomes for women with Medicaid coverage at delivery. We evaluate six variables; three variables were new additions on the 2003 birth certificate (Medicaid enrollment at birth, prepregnancy body mass index, and breastfeeding initiation), and the other three variables have shown to be unreliable but are of significant policy research interest (prepregnancy smoking, diabetes, and hypertension).