Adolescent pregnancy is a global issue. Early childbearing is strongly linked to poverty and negative health outcomes, including increased neonatal death risk. This study explores spatial patterns of adolescent pregnancies and neonatal deaths and their association with socioeconomic characteristics.

This population-based study used spatial analysis techniques to investigate the geographical distribution of adolescent pregnancies, socioeconomic characteristics and neonatal mortality rate (NMR).

The 645 municipalities of State of Sao Paulo, Brazil.

All live births to mothers residing in the State of Sao Paulo, Brazil, between 2004 and 2020.

The socioeconomic indicators used were: municipal human development index and per capita income (PCI). Spatial patterns were assessed for spatial autocorrelation (Moran’s I, LISA), and smoothed using local Bayesian estimation. Spearman’s correlation was used to ascertain the relationship between the percentage of live births to adolescent mothers and socioeconomic indexes. This calculation was also undertaken between different maternal age groups of NMR.

The study analysed over 10 million live births, with 14.3% attributed to adolescent mothers. Spatial analysis revealed significant clustering of adolescent pregnancies, strongly associated with lower socioeconomic indicators. NMR also exhibited spatial clustering, particularly after smoothing. Statistically significant differences were observed in PCI medians between high–high and low–low clusters for adolescent births. High and low incidence areas of NMR, both in all maternal ages and stratified by adolescent and non-adolescent mothers, demonstrated considerable overlap.

The results indicated the existence of clustering areas of adolescent pregnancy and neonatal deaths and suggested that the prevalence of births to adolescent mothers is not distributed equally and is higher in lower socioeconomic developed areas.