The enduring burden of short birth intervals on child survival: A 28-year trend analysis in Burkina Faso

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Résumé

Child survival has improved considerably over the past decades in sub-Saharan Africa, yet preventable risk factors such as closely spaced births continue to threaten progress, especially in fragile contexts. This study examines the association between interbirth intervals and under-five survival in Burkina Faso using data from five rounds of Demographic and Health Surveys conducted between 1993 and 2021. The study combines descriptive survival analysis (e.g., Kaplan–Meier curves, log-rank tests) with Cox proportional hazards models to estimate the adjusted association between interbirth intervals and under-five mortality, while controlling for maternal, child, household, and contextual characteristics. The results show that short interbirth intervals (<24 months) are consistently associated with excess mortality, following a markedly non-linear trajectory: the adjusted hazard ratio declines from 2.50 (95% confidence interval: 1.56–4.0) in 1993 to 1.49 (1.04–2.14) in 1998–1999 and 1.63 (1.27–2.1) in 2003, then rises to 1.97 (1.64–2.38) in 2010 and peaks at 3.20 (2.28–4.49) in 2021. In contrast, the protective advantage of long intervals (≥36 months), significant from 1998 to 2010, disappears in the most recent survey. These dynamics suggest that health system strengthening and expanded access to care have mitigated part of the vulnerability associated with closely spaced births, but that these gains remain fragile in the context of escalating security crisis and persistent socio-territorial inequalities. Over time, under-five survival appears increasingly shaped by socioeconomic (e.g., household wealth, maternal education), territorial (e.g., rural residence, conflict-affected regions), and biological factors (e.g., low birth weight, extreme maternal ages). In this context, the enduring burden of mortality linked to short interbirth intervals, particularly among poor rural households and adolescent mothers, calls for geographically and socially targeted family planning strategies, embedded within an integrated package of maternal and child health, nutrition, vaccination, and equitable access to quality healthcare services.

Mots-clés

Under-five; mortality; Birth spacing; Determinants; Burkina Faso