Epidemiological insights into neural tube and orofacial malformations in Chile using data from the National Registry of Congenital Anomalies (RENACH)

Background: Congenital anomalies affect approximately 6% of global births annually and contribute significantly to infant mortality and long-term disability. Low folate status has been linked to malformations such as neural tube defects (NTDs) and orofacial clefts (OFCs). This work aimed to estimate the national prevalence of these two groups of malformations in Chile, a country subjected to mandatory folic acid fortification of flour. We also analyzed the sex dimorphism of the NTD and OFC and described the main associated comorbidities. Methods: In this cross-sectional descriptive study, we used data from the Chilean National Registry of Congenital Anomalies (2016–2017) to analyze NTD and OFC prevalence and sex bias. Results: The study included 3,376 records, revealing a total of 7.63/10,000 births for NTD patients and 12.01/10,000 for OFC patients. Anencephaly and cleft lip/palate were the most prevalent subtypes in the NTD and OFC. Sex-related differences were noted, with a significantly greater prevalence of cleft lip/palate and cleft lip in males and a tendency toward a greater prevalence of anencephaly in females. Approximately 70% of NTD cases were isolated; associated malformations primarily involved the nervous, musculoskeletal, and facial systems. Isolated OFC accounted for 77% of cases, with musculoskeletal and neurological malformations being the most frequently associated. Conclusions: NTD and OFC prevalence and sex-specific variations are consistent with estimates in countries that apply mandatory folic acid fortification policies. This study provides valuable insights into the epidemiology of NTDs and OFCs in Chile and emphasizes the importance of ongoing surveillance through standardized data collection.