To determine the effects of a school-based, nurse-run prenatal counseling program, records of prenatal care visits of students and their infants' birth weights (i.e., cases) were obtained from the state live birth certificate tape for 1985-1987. From the same tape, a mother residing in the same community but not enrolled in the program was matched with each case on eight criteria to serve as a control. A total of 288 matched case-control pairs were obtained. Using McNemar's test, a significantly higher percentage of the cases received adequate prenatal care than did the controls.