Group Prenatal Care Reduces Risk of Preterm Birth and Low Birth Weight: A Matched Cohort Study

Background: Group prenatal care is a promising strategy to improve perinatal outcomes. Research in larger more diverse populations with attention to adherence is needed to inform clinical practice recommendations. We examined the impact of group prenatal care on preterm birth and low birth weight in a large metropolitan hospital, accounting for patient adherence, over an 8.5-year period. Materials and Methods: We analyzed data from 9,348 pregnant women with a live, singleton birth who received group (CenteringPregnancy or Expect With Me) or individual prenatal care at Vanderbilt University Medical Center from January 2009 through June 2016. Propensity scores were used for matching based on year of delivery, age, race, pregnancy risk, and adequacy of care. The propensity score matched sample included 1,384 group and 5,055 individual prenatal care patients (total=6,439 women). Preterm birth (<37 weeks gestation) and low birth weight (<2,500g) were obtained from systematic medical review. Risks were estimated using Poisson regression. Results: Controlling for individual visits, receiving group prenatal care resulted in significantly lower risk of having a preterm birth (Rate ratio [RR] 0.63, 95% confidence interval [CI] 0.49-0.81) and low birth weight baby (RR 0.62, 95% CI 0.47-0.81), compared to receiving individual care only. Women with 5 group prenatal care visits experienced even greater benefits: 68% (RR=0.32; 95% CI 0.22-0.45) and 66% (RR=0.34; 95% CI 0.23-0.50) risk reduction in preterm birth and low birth weight, respectively. Conclusions: Participation in group prenatal care may improve birth outcomes. Efforts to promote adoption and sustainability of group prenatal care by health systems may be warranted.