Genetic Contributions to Preterm Birth Study

Project Timeline: 5/17/2010 - 9/30/2011

Preterm deliveries a major cause of infant morbidity and mortality in the United States. Data from an earlier study examined the maternal and infant genetic contributions to preterm birth. Study subjects were selected from the California birth certificate record based on last menstrual period (LMP)-based gestational age estimates in the birth certificate. California adopted the 2003 version of the national birth certificate in January 2007 the 2003 revision includes information on the obstetric estimate of gestational age. This project sought out to determine whether the obstetric estimate on the revised birth certificates would be a suitable substitute for LMP-based estimate for future studies of gestational age. In collaboration with the California Department of Health Services, Sequoia foundation staff linked California birth and death records to data collected by CDHS’s Genetic Disease Screening Program’s Prenatal Screening (PNS) and Newborn Screening Programs. The purpose was to compare multiple methods of dating pregnancies and the potential impact on preterm delivery rate estimates.

The aims of this analysis were to:
1) Compare gestational age from the obstetric estimate on birth records to ultrasound and LMP estimates from the PNS program, and explore factors related to discrepancies;
2) estimate accuracy of gestational age estimates in the PNS system using medical records as the gold standard (medical record reviews have already been completed for the case-control study);
3) Determine whether preterm rates have declined in California overall and among specific race/ethnic groups between 1996 and 2008 based on LMP from birth records and other dating methods including ultrasound from prenatal screening records; and
4) Estimate the contribution of genetic and environmental factors in changing fetal death rates to preterm delivery rates in California.