Available data sources to estimate adolescent birthrates in Mexico: a users' guide

Research, policymakers, and advocacy groups rely on valid estimates of adolescent births to inform their work. Estimates of births among very young adolescents (10-14 years old) are especially lacking.

We compared adolescent fertility rates in Mexico across the census, population-based surveys, civil registration, and birth certificates. We calculate live birth rates among very young adolescents (VYA; 10-14 and 12-14) and older adolescents (15-19) in Mexico, at national and state levels, and by year (2008-2019). We compare estimates with official reconciled data from the Mexican government. For context, we also calculate all other age-specific fertility rates (ASFRs) and total fertility rates (TFRs).

Overall, all national-level data sources in the period studied show declines in TFR and ASFRs for adolescents. Official government estimates for older adolescents (15-19) declined from 78·3 to 65·1 births per 1,000 adolescents 15-19 years old between 2008 and 2019. Rates for VYAs showed a decline in hospital registration (from 3·5 to 2·8 births per 1,000 adolescents aged 12 to 14 years old), and vital statistics (from 2·6 to 1·9) compared with the census. At the state level, VYA birth rates calculated using SINAC are higher than those estimated with vital statistics; the census estimates, at only three timepoints, are variable by state.

Four different publicly available data sources in Mexico produce adolescent birthrate estimates that are largely consistent with official reconciled data, validating the use of each of these data sources individually. For VYA estimates, which the government does not include in population projections, hospital registration (birth certificates) may be the best source.