Short and long birth intervals are known to adversely affect infant and child mortality, and short birth intervals in particular can impede maternal nutrition repletion in low-income settings. The effect of the length of time between pregnancies and their outcomes on subsequent maternal and child morbidity and mortality warrant accurate and full understanding. There is limited consensus on the optimal length of a birth interval associated with lower risk of child death. The observed effects of birth spacing themselves can be decomposed and attributed to several key underlying behaviors and conditions, i.e., breastfeeding, sexual abstinence, contraceptive practice, maternal nutrition, physical exertion, and infections. Collectively these impact fetal growth, safe delivery and subsequent maternal and child mortality risk. Maternal and child health programs that promote birth spacing will be better served with a strong evidence base that connects specific measures and interventions—breastfeeding, family planning, nutritional supplementation, and infectious disease prevention—with the relevant periods in a birth interval when their benefits are strongest.
CHERG will form a small core group of maternal, reproductive and child health experts to conduct a rigorous search for all available, appropriate and accessible data sets with information on birth spacing in relation to child and maternal survival risk. A principal investigators’ collaborative group will develop an analytic plan that will enable understanding the risk-related components of birth spacing. Specifically, the group will systematically evaluate published research findings on optimal birth spacing length in relation to early, neonatal, post-neonatal, and infant-mortality as a first set of outcomes, and then with child nutrition, under 5 child mortality, and maternal mortality as a second set of outcomes. The next step of empirical data analysis will be informed by these review results and will assess the individual influences of three periods that make up birth intervals—the duration of breastfeeding, the duration of contraceptive coverage, and the residual non-lactating/non-contracepting period. In this latter period, other factors such as abstinence, infection-related sub-fecundity or early fetal loss contribute time to the next pregnancy and affect its outcome. The potential confounding from maternal, health care, and environmental factors will be thoroughly considered, as will statistical interactions between the three periods, particularly overlapping periods of breastfeeding and contraception.
The statistical modeling will shed light on the relative importance of breastfeeding or contraception on birth spacing length in regard to child and maternal survival. The results will be further used to estimate the amount of change required in birth interval distributions and shifts in breastfeeding and contraceptive use patterns, to achieve hypothetical reductions, e.g., 10, 15, 20 percent, in child mortality at different stages of life. Similarly patterns of economic inequity in maternal and child mortality risk due to differential birth spacing will also be examined. The final results will be reviewed at a meeting of the working group scheduled toward the end of the analysis period.
Ahmed S, Li Q, Liu L, Tsui AO. Maternal deaths averted by contraceptive use: an analysis of 172 countries. Lancet. 2012. 380(9837):111-25.
Cleland J, Conde-Agudelo A, Peterson H, Ross J, Tsui A. Contraception and Health. Lancet. 2012. 380(9837); 149-156.