A new method for calculating Adequacy of Pre-Natal Care Utilization

Many authorities believe that adequate prenatal care result in better pregnancy outcomes, including reduced maternal and infant mortality and morbidity, reduced risk for pre-term delivery and low birth weight. Two indices measuring adequacy of prenatal care utilization generally used for public health research, program and policy planning, and resource allocation, are the Kessner Index and the Kotelchuk Adequacy of Pre-Natal Care Utilization Index (APNCU). Both indices utilize data collected on the birth certificate, specifically, the month of pregnancy that prenatal care began. This item was replaced by the exact dates of first and last prenatal care visit in the 2003 revision of the U.S. Standard Certificate of Birth. These data changes in the birth certificate present an opportunity to reconsider the APNCU. The Kotelchuck Index is widely used and most users still employ Dr. Kotelchuk's 1996 SAS program to calculate the APNCU. In keeping this index for the surveillance of prenatal care, APNCU users end up utilizing partial data from the new variables, the month information from the prenatal care started date and last menstrual date. We propose a new index based on birth date and prenatal care started date, thus exploiting the full date variable now available in the revised birth certificate. Using Pennsylvania live birth certificate data for Montgomery County, this study compares the results of the two methods of calculation. In the comparison, our proposed index is a stronger predictor of low birth weight, a critical birth outcome indicator, than the Kotelchuk Index.