Predicting preterm birth among participants of North Carolina's Pregnancy Medical Home Program

Background: Preterm birth prior to 37 weeks gestation is the leading cause of infant death and long-term neurological disabilities in the United States. In response to the high rates of poor birth outcomes in North Carolina, a new program began in 2011 to provide evidence-based, high quality maternity care to pregnant Medicaid beneficiaries. Community Care of North Carolina’s (CCNC) Pregnancy Medical Home (PMH) program identifies patients at risk of poor birth outcomes through a standardized risk screening and refers them for care management to address those risk factors. The purpose of this analysis is to determine which combination of risk factors from the screening tool is most predictive of preterm birth by race/ethnicity and parity. Methods: This retrospective cohort includes women screened before 24 weeks gestation who delivered a live birth in N.C. between September 2011-2012 (N=15,186). Data come from CCNC’s Case Management Information System and birth certificates. Logistic regression with backward stepwise elimination is used to arrive at the final models. Results: The prevalence of preterm birth was 11%. Multiple gestation, a previous preterm birth, cervical insufficiency, chronic diabetes and hypertension were the strongest risk factors with odds ratios ranging from 2.49 to 10.01. A fetal death, being underweight, smoking during pregnancy and other chronic diseases were additional statistically significant predictors. Different combinations of risk factors were significant among subgroups defined by race/ethnicity and parity. Conclusions: Salient risk factors for preterm birth can be identified for certain subgroups which will allow for better targeted approaches for preterm birth prevention.