Anencephaly in Brazil: an ecological study on sociodemographic factors and prenatal care

Anencephaly is a serious and fatal congenital anomaly. It can be detected in the first trimester of pregnancy through an ultrasound performed during prenatal care. This study aimed to identify maternal and prenatal care factors that predict anencephaly in Brazil.

This was an ecological observational study using secondary data on live births in Brazil between 2017 and 2022. The study variables were grouped into maternal sociodemographic factors (Brazilian regions, maternal age, marital status, schooling and race/color) and prenatal care (consultations performed, gestational week (time) and month of onset of care). A multivariate binary logistic regression model was used.

The results obtained through the multivariate analysis of maternal sociodemographic factors showed that the southern region (p = 0.005) had a lower association with maternal sociodemographic factors than did the northern region; married (p = 0.002) and widowed (p = 0.007) marital statuses had a greater association with maternal sociodemographic factors than did single marital status; and any education of less than 11 years or no schooling had a greater chance (p < 0.001) of neonates being born with anencephaly. For the prenatal care variables, the number of visits was less than 6 (p < 0.004) and was related to a higher prediction, and gestation time > 22 weeks (p < 0.001) was related to a lower association with anencephaly.

We concluded that the predictors of anencephaly in Brazil for sociodemographic and prenatal factors were being in the Northeast Region, being married or widowed, having a low level of schooling, having a low number of consultations, and having premature births.