Integrating group antenatal care into routine services: a registry-based cohort study in Geita, Tanzania

BACKGROUND: Group antenatal care (G-ANC) is an emerging service delivery model that integrates clinical assessments, health education, and peer support within group sessions. While evidence supports its effectiveness in pilot settings, less is known about its feasibility and impact when integrated into routine public health systems in low-resource settings. METHODS: We conducted a registry-based observational cohort study (January 2023-November 2024) across six government facilities in Geita Region, Tanzania (two hospitals, two health centers, and two dispensaries). Pregnant women with gestational age ≥ 20 weeks were enrolled into G-ANC cohorts. Data was abstracted from routine antenatal care (ANC), labor and delivery, and cohort records. Descriptive statistics summarized ANC attendance and service uptake; associations with adverse birth outcomes were examined using a binomial-logit generalized linear mixed model (GLMM). RESULTS: A total of 5936 women in 149 cohorts were enrolled. Overall, 93.9% completed ≥ 4 ANC visits (ANC4 +); 76.1% received ≥ 3 doses of malaria intermittent preventive treatment in pregnancy with sulfadoxine-pyrimethamine (IPTp3 +); 92.6% received iron-folate supplementation; and 96.2% delivered in health facilities. Only 8.5% initiated ANC in the first trimester, consistent with the ≥ 20-week threshold for G-ANC entry. In multivariable GLMM, completing ≥ 4 ANC visits was associated with lower odds of adverse birth outcomes (adjusted odds ratio [aOR] = 0.122, 95% CI 0.06-0.24; p < 0.001). Attendance at hospital-level facilities was associated with higher odds (aOR = 2.91, 95% CI 1.37-6.18; p = 0.005), likely reflecting referral of high-risk pregnancies. First-trimester initiation showed no significant association (aOR = 1.04, 95% CI 0.27-3.93). CONCLUSIONS: In routine settings, G-ANC was associated with high ANC attendance, strong uptake of essential interventions, and positive birth outcomes. Integration appears feasible within public systems, though adaptations are needed to promote earlier initiation and alignment with the WHO eight-contact model. Further research should examine costs, feasibility, scalability, and long-term impact.