196: The impact of centeringpregnancy group prenatal care on preterm birth

Abstract

CenteringPregnancy group prenatal care (GPNC) has shown promise in reducing preterm births (PTB), but the mechanism is not clear. We hypothesize that the GPNC model may reduce spontaneous PTB (sPTB), but would be less likely to influence indicated PTB (iPTB). We also sought to compare other birth outcomes, including low birth weight (LBW), and neonatal intensive care unit (NICU) admissions. Retrospective cohort study examining the influence of GPNC on PTB among a group of Medicaid eligible and medically low-risk women delivering at a single institution between April 2009 - March 2014. Participation in GPNC was voluntary. Birth outcome data from vital statistics records were appended to patient records, and detailed chart abstraction was performed for women with PTB to determine sPTB versus iPTB. Women attending ≥1 GPNC session were included in the GPNC group. Consistent with the GPNC model, women with multiple gestation, pregestational diabetes, BMI >45, and late entry to prenatal care (>5 months) were excluded. Demographic characteristics of women in GPNC versus individual prenatal care (IPNC) were compared through bivariate analysis and birth outcomes were analyzed through generalized estimating equations using log binomial regression. The final analysis included 1292 women in GPNC, and 8703 in IPNC. When compared to women in IPNC, women in GPNC were younger, more often non-Hispanic Black, had more education, less likely to be married, more likely to be primigravid, and less likely to have a previous PTB. Women in GPNC also entered prenatal care earlier in gestation, and were less likely to have inadequate prenatal care (P<0.01 for all). Participants in GPNC had lower rates of PTB (6.5% vs. 13.0%, P<0.01), sPTB (5.0% vs. 10.1%, P<0.01). After controlling for potential confounders, the risk of PTB (RR 0.38; 95% CI 0.31-0.47, P<0.01) and sPTB (RR 0.49; 95% CI 0.38-0.63, P<0.01) were reduced in GPNC compared to IPNC. Additionally, women in GPNC had fewer LBW infants (RR 0.46, 95% CI 0.37-0.56, P<0.01) and fewer NICU admissions (RR 0.46; 95% CI 0.37-0.57, P<0.01). Participation in GPNC demonstrated a decreased risk of overall PTB and sPTB, as well as LBW and NICU admissions. These findings add new insight into the possible mechanisms underlying improvements in PTB rates seen for women in GPNC. Prospective studies are needed to eliminate selection bias.