Background — The main objective of the current study is to examine the trend of congenital abnormalities among children born by women with and without diabetes, and to explore the impact of food fortification by folic acid on the rate of birth defects among these two groups of mothers.
Methods — All children born alive in Ontario, Canada, during 1994 to 2009 and their mothers were included in study. Diagnosis of pregestational diabetes among mothers was identified using Diabetes registry, and diagnosis of birth defects among children were identified using hospital records.
Results — The prevalence of births among diabetic mothers increased by almost 200% during the study period. Among children born to mothers with diabetes, the prevalence for all anomalies combined was approximately 47% higher and for various cardiac and central nervous system anomalies up to a three- to fivefold higher than those born to nondiabetic mothers. While the rate of birth defects in both groups observed a considerable decline after food fortification in 1999, but the gap between two groups remained unchanged over time.
Conclusion — While the prevalence of birth defects among diabetic pregnancies is still considerably higher that nondiabetic pregnancies, results of the current study indicate a declining trend in the prevalence of some congenital abnormalities among babies born to both diabetic and nondiabetic mothers after 1999. We need to be more aggressive in implementing preventive measures, including a national diabetes plan or the proposed universal policy of supra-dietary folic acid supplementation for women with diabetes who are of reproductive age.