Trends and determinants of institutional childbirth among women of reproductive age in Tanzania: evidence from four Demographic and Health Surveys (2004/05-2022)

Institutional delivery is a vital intervention for reducing maternal mortality, especially in low and middle-income countries like Tanzania. Although there have been significant improvements in maternal health services over the last two decades, disparities in institutional delivery continue, and most studies examining these disparities have used only a single cross-sectional dataset. This study aimed to assess long-term trends and identify predictors of institutional delivery in Tanzania, using data from four rounds of the Tanzania Demographic and Health Surveys (TDHS) from 2004/05 to 2022. We analysed pooled data from four rounds of the TDHS. The study included women of reproductive age (15–49 years) who had given birth within five years prior to each survey. Descriptive analyses were conducted to examine trends in institutional delivery. A modified Poisson regression model with robust variance was employed to directly estimate adjusted prevalence ratio (APR), providing a more interpretable measure of association than the odds ratio, which may overestimate the effect size for common outcomes. APR with corresponding 95% Confidence Intervals (CI) were presented to estimate the strength and magnitude of association. Institutional delivery rates rose from 47% in 2004/05 to 80% in 2022, indicating substantial improvements in maternal health service utilization. Compared to women with no education, those with primary (APR:1.67,95% CI: 1.33–2.09) and secondary or higher education (APR:3.06, 95% CI: 2.09–4.48) were more likely to deliver in a health institution facility. Women from the middle (APR:1.36, 95% CI: 1.05–1.77) and high-income households (APR:2.21, 95% CI: 1.38–3.54) had higher institutional delivery use compared to those from poor households. Four or more antenatal care (ANC) visits (APR:1.50,95% 1.09–2.05) and perceived distance as not a big problem (APR:2.34,95% 1.90–2.89) were also positively associated with institutional delivery facility. In contrast, women with two or more previous births were less likely to deliver in a health facility compared to first-time mothers (APR:0.54,95% CI:0.43–0.67). While Tanzania has made notable progress in improving delivery coverage, persistent socioeconomic, educational and parity-based inequalities threaten maternal health gains. The findings underscore the pressing need for targeted strategies to enhance maternal education, economic empowerment, and healthcare access, particularly for high-parity and socioeconomically disadvantaged women, in order to sustain and further improve maternal health outcomes in Tanzania.