Birth defects in the Brazilian side of the triple border: a population-based cross-sectional study

Background Major birth defects are characterized by its severity and are a public health challenge since it chronically affects the population. Foz do Iguassu is located in Brazili's largest international border and presents a birth defect rate 50% greater than the country's average. Methods Identifying factors associated to birth defects is important to guide preventive actions toward modifiable risk factors and target the most susceptible population. In this cross-sectional study we measured the prevalence of major birth defects and associated maternal sociodemographic factors in Foz do Iguassu. Data were collected from a governmental registry and included all births that occurred in the city between 2012 to 2017. The variables measured were maternal education, maternal race, country of residence, maternal parity and onset of prenatal care. Data were analyzed through logistic regression models to verify the maternal sociodemographic factors associated with major birth defects. Results 26,214 births were analyzed; among the 305 birth defects registered, 140 (46%) corresponded to a major birth defect. Cleft lip and/or palate and gastroschisis were the most prevalent major birth defect (9.5/10,000 live births and 6.83/10,000 live births, respectively). Maternal education up to 7 years was the only variable associated with the major birth defects (ORadj=1.58; CI = 1.07-2.33; p = 0.02). Maternal age was associated with gastroschisis (mean: 21.5 years; p = 0.002) and Down syndrome (mean: 33.5 years; p = 0.007). Conclusions In this area, cleft lip and/or palate and gastroschisis are the most common major birth defects, and maternal education is weakly associated with major birth defects. Key messages The epidemiology of major birth defects in this area differs from Brazil’s. Future research should focus on inherent risk factors for congenital defects and exposure to teratogens.