Inflammatory markers in serum and placenta in a randomized controlled trial of group prenatal care

BACKGROUND: Racial and socioeconomic disparities in preterm birth and small for gestational age births are growing in the United States, increasing the burden of morbidity and mortality particularly among Black women and birthing persons and their infants. Group prenatal care is one of the only interventions to show potential to reduce the disparity, but the mechanism is unclear. OBJECTIVE: The goal of this project was to identify if group prenatal care, when compared with individual prenatal care, was associated with a reduction in systemic inflammation during pregnancy and a lower preva-lence of inflammatory lesions in the placenta at delivery.STUDY DESIGN: The Psychosocial Intervention and Inflammation in Centering Study was a prospective cohort study that exclusively enrolled participants from a large randomized controlled trial of group prenatal care (the Cradle study, R01HD082311, ClinicalTrials.gov: NCT02640638) that was performed at a single site in Greenville, South Carolina, from 2016 to 2020. In the Cradle study, patients were ran-domized to either group prenatal care or individual prenatal care, and survey data were collected during the second and third trimesters. The Psychosocial Intervention and Inflammation in Centering Study cohort additionally provided serum samples at these 2 survey time points and permitted collection of placental biopsies for inflammatory and histo-logic analysis, respectively. We examined associations between group prenatal care treatment and a composite of z scored serum inflamma-tory biomarkers (C-reactive protein, interleukin-6, interleukin-1 recep-tor antagonist, interleukin-10, and tumor necrosis factor a) in both the second and third trimesters and the association with the prevalence of acute and chronic maternal placental inflammatory lesions. Analyses were conducted using the intent to treat principle, and the results were also examined by attendance of visits in the assigned treatment group (modified intent to treat and median or more number of visits) and were stratified by race and ethnicity. RESULTS: A total of 1256 of 1375 (92%) Cradle participants who were approached enrolled in the Psychosocial Intervention and Inflammation in Centering Study, which included 54% of all the Cradle participants. The Psychosocial Intervention and Inflammation in Centering Study cohort did not differ from the Cradle cohort by demographic or clinical characteris-tics. Among the 1256 Psychosocial Intervention and Inflammation in Centering Study participants, 1133 (89.6%) had placental data available for analysis. Among those, 549 were assigned to group prenatal care and 584 of 1133 were assigned to individual prenatal care. In the intent to treat and modified intent to treat cohorts, participation in group prenatal care was associated with a higher serum inflammatory score, but it was not associated with an increased prevalence of placental inflammatory lesions. In the stratified analyses, group prenatal care was associated with a higher second trimester inflammatory biomarker composite (modified intent to treat: B=1.17; P=.02; and median or more visits: B=1.24; P=.05) among Hispanic or Latine participants. CONCLUSION: Unexpectedly, group prenatal care was associated with higher maternal serum inflammation during pregnancy, especially among Hispanic or Latine participants.