Patterns and determinants of short and long birth intervals among women in selected sub-Saharan African countries

Optimal birth spacing (defined as a birth spacing of 24-59 months) is incontrovertibly linked to better health outcomes for both mothers and babies. Using the most recent available Demographic and Health Survey data, we examined the patterns and determinants of short and long birth intervals among women in selected sub-Saharan African (SSA) countries.Reproductive health and sociodemographic data of 98,934 women from 8 SSA countries were analyzed. Unadjusted and adjusted multinomial logistic regression models were used to examine the net relationship between all the independent variables and short and long birth intervals.Overall, the majority of women in all the countries optimally spaced births. However, a significant proportion of women had short birth intervals in Chad (30.2%) and the Democratic Republic of Congo (Congo DRC) (27.1%). Long birth spacing was more common in Eastern and Southern African countries, with Zimbabwe having the highest rate of long term birth interval (27.0%). Women who were aged 35 years and above in Uganda (RRR = 0.72, CI = 0.60-0.87), Tanzania (RRR = 0.62, CI = 0.49-0.77), Zimbabwe (RRR = 0.52, CI = 0.31-0.85), Nigeria (RRR = 0.82, CI = 0.72-0.94) and Togo (RRR = 0.67, CI = 0.46-0.96) had significantly lower odds of having short birth intervals compared to women aged 15-24 years. Older women (above 34 years) had increased odds for long birth intervals in all countries studied (Chad (RRR = 1.44, CI = 1.18-1.76), Congo DRC (RRR = 1.73, CI = 1.33-2.15), Malawi (RRR = 1.54, CI = 1.23-1.94) Zimbabwe (RRR = 1.95, CI = 1.26-3.02), Nigeria (RRR = 1.85 CI = 1.56-2.20), Togo (RRR = 2.12, CI = 1.46-3.07), Uganda (RRR = 1.48, CI = 1.15-1.91), Tanzania RRR = 2.12, CI = 1.53-2.93).The analysis suggested that the determinants of long and birth intervals differ and varies from country to country. The pattern of birth spacing found in this study appears to mirror the contraceptive use and fertility rate in the selected SSA countries. Birth intervals intervention addressing short birth intervals should target younger women in SSA, especially in Chad and Congo DRC, while intervention for long birth spacing should prioritize older, educated and wealthy women.