Studies have described correlation of pre gestational diabetes mellitus (PGDM) with the risk of congenital heart defects (CHDs). Given the uncertainty concerning the correlations between maternal PGDM and gestational diabetes mellitus (GDM) and the risk of specific types of CHDs and congenital anomalies (CAs) in other systems, researchers sought to determine type-specific CAs in offspring of women with diabetes. In addition, they investigated to what extent types of maternal diabetes are linked with elevated risk of CAs in offspring.

• Researchers suggest this work to be the first comprehensive systematic review and meta-analysis of population-based studies of over 80 million participants establishing an elevated risk of type-specific CAs, especially CHDs, in offspring born to women with pre-gestational or gestational diabetes.

• An association of maternal pre gestational diabetes was observed with a significant rise in the risk of 38 out of 45 categories of CAs in offspring, while a small but significant rise in the risk of 16 out of the 45 categories appeared to be correlated with maternal gestational diabetes.

• Offspring of women with pre-gestational diabetes are at higher corresponding relative risks (RRs) of overall CAs/CHDs than offspring of women with gestational diabetes, with no overlap in the 95% CIs.