<b>Determinants and Gaps Influencing Maternal Health Service Utilization and Zero-Dose Immunization in Nigeria: A Continuum of Care Analysis Across Six Nigerian States</b>

<b>Background:</b><br>Despite ongoing health reforms and international investment, Nigeria continues to experience high maternal and child mortality, with significant disparities in service utilization. Gaps in antenatal care (ANC), skilled birth attendance, institutional delivery, and child immunization, particularly zero-dose status, represent missed opportunities along the reproductive, maternal, newborn, and child health continuum of care. This study aimed to examine the interconnected determinants of care utilization across this continuum and identify factors associated with no, partial, and complete service uptake.<b>Methods:</b><br>A cross-sectional household survey was conducted in six Nigerian states (Gombe, Kaduna, Kano, Katsina, Lagos, Niger) as part of a baseline assessment for the Collaborative Learning on Data Use for Action initiative by CHAI. Using a multistage probability sampling design, data were collected from 1,958 women of reproductive age (15-49 years) with recent live births. Structured questionnaires captured data on utilization of four key services (ANC attendance, place of delivery, type of birth attendant, and child immunization status), alongside socioeconomic and demographic factors. Descriptive analyses, chi-square tests, and multinomial logistic regression were applied to explore predictors of care utilization and zero-dose status.