Group vs traditional prenatal care for improving racial equity in preterm birth and low birthweight: the Centering and Racial Disparities randomized clinical trial study.

Background: The United States has persistently high rates of preterm birth and low birthweight and is characterized by significant racial disparities in these rates. Innovative group prenatal care models, such as CenteringPregnancy, have been proposed as a potential approach to improve the rates of preterm birth and low birthweight and to reduce disparities in these pregnancy outcomes.

Objective: This study aimed to test whether participation in group prenatal care would reduce the rates of preterm birth and low birthweight compared with individual prenatal care and whether group prenatal care would reduce the racial disparity in these rates between Black and White patients.

Study Design: This was a randomized controlled trial among medically low-risk pregnant patients at a single study site. Eligible patients were stratified by self-identified race and ethnicity and randomly allocated 1:1 between group and individual prenatal care. The primary outcomes were preterm birth at <37 weeks of gestation and low birthweight of <2500 g. The primary analysis was performed according to the intent-to-treat principle. The secondary analyses were performed according to the as-treated principle using modified intent-to-treat and per-compliance approaches. The analysis of effect modification by race and ethnicity was planned.

Results: A total of 2350 participants were enrolled, with 1176 assigned to group prenatal care and 1174 assigned to individual prenatal care. The study population included 952 Black (40.5%), 502 Hispanic (21.4%), 863 White (36.8%), and 31 "other races or ethnicity" (1.3%) participants. Group prenatal care did not reduce the rate of preterm birth (10.4% vs 8.7%; odds ratio, 1.22; 95% confidence interval, 0.92-1.63; P=.17) or low birthweight (9.6% vs 8.9%; odds ratio, 1.08; 95% confidence interval, 0.80-1.45; P=.62) compared with individual prenatal care. In subgroup analysis, greater attendance in prenatal care was associated with lower rates of preterm birth and low birthweight. This effect was most noticeable for the rates of low birthweight for Black participants in group care: intent to treat (51/409 [12.5%]), modified intent to treat (36/313 [11.5%]), and per compliance (20/240 [8.3%]). Although the rates of low birthweight were significantly higher for Black participants than White participants seen in individual care (adjusted odds ratio, 2.00; 95% confidence interval, 1.14-3.50), the difference was not significant for Black participants in group care compared with their White counterparts (adjusted odds ratio, 1.58; 95% confidence interval, 0.74-3.34).

Conclusion: There was no difference in the overall rates of preterm birth or low birthweight between group and individual prenatal care. With increased participation in group prenatal care, lower rates of preterm birth and low birthweight for Black participants were observed. The role of group care models in reducing racial disparities in these birth outcomes requires further study.