Bayesian spatial modelling of contraception effects on fertility in Mexican municipalities in 2020

The prevalence and use of contraceptive methods is an essential element to explain the behaviour of fertility and population growth. The objective of this study was to analyse the spatial correlation between the use of contraceptive methods in women of childbearing age and fertility levels observed in Mexico's municipalities in 2020. Data on contraceptive use are from the National Survey of Demographic Dynamics (ENADID) 2018, while fertility rates were estimated from vital statistics and population census data. Three Bayesian spatial models including fixed effects, random effects and spatial effects were employed. The models were estimated using the integral nested Laplace approximation (INLA) package available in the R language. The results reveal the existence of important regional inequalities associated with the use and prevalence of contraceptive methods, which generate marked differences in observed levels of fertility between municipalities.