Estimated numbers of births and pregnancies in the Americas

To estimate the annual numbers of pregnancies and births per 1x1km grid cell in 2015, previous WorldPop methods (1,2,3) were adapted for the Americas region. High spatial resolution estimates of population counts per 100x100m grid cell for 2015 were recently constructed for Latin American and Caribbean countries [1]. With consistent subnational data on sex and age structures, as well as subnational age-specific fertility rate data across the Americas currently unavailable for fully replicating the approaches of [2], national level adjustments were made to construct pregnancy counts. Data on estimated total numbers of births [5] and pregnancies [6] occurring annually in 2012 were assembled for all Latin American study countries, as well as births in 2015 [5]. As no 2015 pregnancies estimates exist at present, the ratios of births to pregnancies for each country in the Americas were calculated using the 2012 estimates, and then these were applied to the 2015 births numbers to obtain 2015 estimates of annual pregnancy numbers per-country. This made the assumption that the per-country births:pregnancies ratios remained the same in 2015 as they were in 2012. The 100m spatial resolution gridded population totals data were aggregated to 1km spatial resolution, and the per-country totals were linearly adjusted to match the 2015 pregnancy estimates, to create gridded estimates of numbers of pregnancies across the Americas. Ongoing work is focused on refining these estimates using subnational age-sex structures and age-specific fertility rates, following previous approaches [1,2,3], to better account for subnational variations within countries.