Impact of high altitude exposure during pregnancy on the frequency of congenital anomalies associated with Down syndrome

Abstract

Objective: To determine the impact of exposure to high altitude during pregnancy on the frequency of congenital anomalies coexisting with Down syndrome.

Methods: A retrospective cohort study was conducted in two leading genetics services in Bolivia: the Institute of Genetics of the Universidad Mayor de San Andrés in La Paz and the Laboratory of Genetics and Reproductive Health of the Universidad Mayor de San Simón in Cochabamba, between 2013 and 2022. Cases of patients from all over the country were included, and congenital anomalies were recorded following the EUROCAT 1.5 guide, excluding minor anomalies and considering patent ductus arteriosus as isolated congenital heart disease. Univariate logistic regression was used to compare the prevalence of different congenital anomalies in patients with Down syndrome between both cities.

Results: The study included a sample of 301 cases, of which 182 cases (60.47%) presented some major congenital anomaly. The findings indicate a significant relationship between pregnancy at an altitude above 3000 masl and the development of congenital anomalies (OR = 2.48; 95% CI = 1.50 - 4.14), especially congenital heart disease (OR = 2.18; 95% CI = 1.31 - 3.67), patent ductus arteriosus (OR = 5.82; 95% CI = 1.68 - 36.65) and imperforate anus (OR = 5.29; 95% CI = 1.52 - 33.45).

Conclusion: The study findings suggest that chronic hypobaric hypoxia, which characterizes high altitude, is a risk factor for congenital anomalies, and further research is required to confirm these results. In addition, it is crucial to standardize the reporting of anomalies among different studies in order to have comparable results.