Determinants and gaps influencing zero-dose immunization and maternal Health service utilization in Nigeria: a cross-sectional household survey across six Nigerian states

BACKGROUND: Nigeria continues to experience high maternal and child mortality, despite extensive health reforms and international investment. Missed opportunities across the continuum of care, antenatal care (ANC), skilled birth attendance, facility-based delivery, and child immunization, contribute to these outcomes. Children who receive no vaccines (zero-dose) reflect a key vulnerability in service delivery. OBJECTIVE: To identify factors associated with zero-dose immunization and patterns of maternal healthcare utilization among women in six Nigerian states. METHODS: A cross-sectional household survey was conducted in Gombe, Kaduna, Kano, Katsina, Lagos, and Niger states. A total of 1,958 women aged 15-49 years with recent live births were interviewed. Structured questionnaires captured data on ANC attendance, delivery location and attendant, immunization status, and socio-demographic characteristics. Descriptive statistics, chi-square tests, and multinomial logistic regression were used to assess predictors of maternal and child health service utilization. RESULTS: Only 31% of women received complete care; 58% received partial care, and 11% received none. Zero-dose prevalence was significantly higher among children whose mothers had fewer than four ANC visits (35%), delivered at home (35%), or were attended by unskilled providers (39%). Lower zero-dose rates were found among those delivered in facilities (16%) or by skilled attendants (19%). Key predictors included maternal and paternal education, socioeconomic status, geographic location (notably Kano and Katsina), and maternal age. CONCLUSIONS: Significant disparities in maternal and child health service utilization remain. Expanding ANC coverage, increasing skilled facility-based deliveries, and ensuring postnatal immunization linkage are essential to reduce zero-dose prevalence and promote equity in low-resource settings.