Determinants of Adequate Antenatal Care Attendance in Nigeria: A Survey-Weighted Analysis of the 2018 Demographic and Health Survey

BackgroundNigeria accounts for approximately 19% of global maternal deaths, yet 4 in 10 Nigerian women do not meet the World Health Organization minimum standard of four antenatal care (ANC) visits. Understanding which women are being left behind, and how early they initiate care, is essential for designing effective maternal health programmes. MethodsWe conducted a cross-sectional analysis of 21,465 women with a birth in the five years preceding the 2018 Nigeria Demographic and Health Survey (NDHS). Survey-weighted multivariable logistic regression was used to estimate adjusted odds ratios (aOR) for seven sociodemographic predictors of adequate ANC attendance (4 or more visits). Kaplan-Meier survival analysis and Cox proportional hazards modelling were additionally applied to 16,084 women with complete ANC timing data to examine time to first ANC visit. Confounding was quantified by comparing crude and adjusted estimates. ResultsThe national weighted prevalence of adequate ANC was 57.8% (95% CI: 56.2%-59.4%). The median gestational age at first ANC visit was 5 months, two months later than WHO recommendations. Higher education (aOR = 5.64, 95% CI: 4.45-7.15) and richest wealth quintile (aOR = 3.93, 95% CI: 3.11-4.95) were the strongest independent predictors. Urban residence lost significance entirely after adjustment (aOR = 1.12, p = 0.113), indicating that the crude urban advantage is fully explained by the higher education and wealth of urban women. Educated women initiated ANC 35% faster than uneducated women (HR = 1.35, 95% CI: 1.23-1.47). Confounding was substantial: 74.9% of higher educations crude effect was attributable to correlated socioeconomic factors. ConclusionsEducation and wealth are the dominant independent determinants of both adequate ANC attendance and earlier ANC initiation in Nigeria. The apparent urban advantage is entirely confounded. Targeted investment in girls education, wealth-sensitive demand-side financing, and community-based early ANC outreach particularly in the North West and North East are urgently needed.