Fertility postponement could reduce child mortality: Evidence from 228 Demographic and Health Surveys covering 77 developing countries

Annually, 6 million children under age five die and over 80% of these deaths happen in the developing world. Reducing under-five mortality by two-thirds was a key Millennium Development Goal, but four out of five developing countries lag behind this target. Here we show that postponing fertility could increase child survival. Using data covering 3.3 million births, 77 developing countries, and 228 Demographic and Health Surveys collected from 1985-2014, we are the first to show that secular declines in under-five mortality completely outweigh the risks associated with reproductive ageing. For an individual mother, having a child at an older age means placing the child into a later birth cohort in which survival is higher thanks to secular declines in mortality. Strikingly, there is no limit, as children born to mothers aged 40 or above have the best survival. If fertility in the DHS countries was on average postponed by as little as 1 year, 2.2%, or more than 100,000 of all child deaths per year could be avoided. If expressed preferences for longer birth intervals were realised with an increase in birth spacing by 1 year, child mortality would drop by 3.0% per year. Postponing fertility is not only the expressed preference of women, but would also help save children’s lives.