Objectives: This study assessed how different methods of matching Medicaid records to birth certificates affect Medicaid infant outcome statistics.
Methods: Claims paid by Medicaid for hospitalization of the newborn and for the mother's delivery were matched separately to 1995 North Carolina live birth certificates.
Results: Infant mortality and low-birthweight rates were consistently lower when Medicaid was defined by a matching newborn hospitalization record than when results were based on a matching Medicaid delivery record.
Conclusions: Studies of birth outcomes in the Medicaid population may have variable results depending on the method of matching that is used to identify Medicaid births.