Determinants of congenital anomalies among neonates: a multicenter case–control study in Southwest Shewa Zone, Ethiopia

Congenital anomalies affect nearly 8 million newborns worldwide each year and contribute to long-term disability in approximately 3.2 million children. Although the prevalence of congenital malformations is relatively high in Ethiopia, evidence on their underlying determinants is limited, particularly in Southwest Shewa Zone. This study aimed to assess determinants of congenital anomalies among neonates in Southwest Shewa Zone, Ethiopia. A multicenter, unmatched case–control study was conducted among 245 participants (82 cases and 163 controls) selected through consecutive sampling. Data were collected from mothers using an interviewer-administered questionnaire and review of medical records. Data were entered into EpiData 3.1, and analyzed in SPSS 26. Variables with p-values of ≤ 0.25 in bivariable analysis were entered into the multivariable logistic regression model. Statistical significance was declared at p < 0.05 and adjusted odds ratios (AOR) with 95% confidence intervals ( CI) were reported. Results are presented in texts, tables, and graphs. Lack of folic acid supplementation before and/or during early period of index pregnancy (AOR: 4.99; 95% CI: 2.35–10.95), history of abortion (AOR: 3.56; 95% CI: 1.75–7.39), rural residence (AOR: 3.06; 95% CI: 1.21–8.05), and twin pregnancy (AOR: 3.61; 95% CI: 1.06–12.79) were significantly associated with congenital anomalies. Strengthening preconception and antenatal care services, particularly promoting folic acid supplementation before conception, may help reduce the burden of congenital anomalies. Improved identification, monitoring, and follow-up of women at increased risk, particularly those with adverse reproductive histories and multiple pregnancies, are essential for improving congenital anomalies.