Relationship between interpregnancy interval and congenital

intervals were associated with congenital anomalies. The lowest rate was for the 12-17 months category (1.9%, reference category), and increased rates were seen for both short intervals (2.5% for 0-5 months; adjusted odds ratio, 1.32; 95% confidence interval, 1.01e1.72) and long intervals (2.3% for 24-35 months; adjusted odds ratio, 1.25; 95% confidence interval, 1.02e1.52). Statistically significant associations were also observed for folate independent anomalies, but not for folate dependent anomalies. CONCLUSION: The risk of congenital anomalies appears to increase with both short and long interpregnancy intervals. This study supports the limited existing studies in the literature, further explores the types of anomalies affected, and has implications for further research and prenatal risk assessment.