Prenatal care utilization: its measurement and relationship to pregnancy outcome.

This study proposes a redesigned measure of prenatal care utilization based on modifications made to a preexisting index of the adequacy of such care. Six prenatal care utilization groups were delineated: intensive, adequate, intermediate, inadequate, no-care, and missing/unknown. Using 430,349 cases from South Carolina and North Carolina vital records from 1978 to 1982 (live birth-infant death cohort files for white resident mothers), this proposed prenatal care utilization measure was examined by maternal sociomedical risk characteristics (age-parity, marital status, education, complications of pregnancy, and previous pregnancy terminations) and by pregnancy outcomes (birth weight, gestational age, and birth weight- and gestational age-specific neonatal mortality). The intensive prenatal care group had relatively more pregnancy complications but also the most preferred pregnancy outcomes. Appreciable differences in birth weight and gestational age distributions were observed among the prenatal care categories within maternal risk status groups. Increased utilization of prenatal care was associated with higher mean birth weight and gestational age. However, after controlling for maternal risk status, an appreciable variation in birth weight- and gestational age-specific neonatal mortality was not apparent across prenatal care groups.