Evolution of perinatal outcomes and sociodemographic variables in Chile (1996-2017)

The evolution of birth weight (BW), birth length (BL), and gestational age at delivery (GAD) and their correlation with various maternal sociodemographic variables were studied in Chilean newborns from years 1996 to 2017. A slight decrease in the mean values of these perinatal outcomes was observed; however, their risk sub-categories increased significantly, especially for GAD, indicating an important deterioration. GAD was strongly correlated with BW and BL. In the contingency tables, all sociodemographic variables, with the exemption of sex, had a higher proportion of early term 37-38-week and late pre-term 34-36-week newborns in women with a higher socioeconomic level; the strongest positive association was observed between mother's years of education and the GAD risk category 37-38 weeks. Different maternal factors, such as a higher frequency of cesarean sections, including either obesity presence or smoking habit, could be influencing presented results.