Women with diabetes have considerably higher risk of adverse pregnancy outcomes, such as birth defects than women with no diabetes, a new study shows. The risk is linked to both type 1 and type 2 diabetes.

A Danish study, published in Circulation magazine, researched the medical information of more than 2 million people born between 1978 and 2011. Among those people were more than 7,000 people whose mother had maternal diabetes and 16,000 had congenital heart disease.

The risk of congenital heart disease was around four times higher when the mother had diabetes pre-pregnancy. For every 1,000 diabetic mothers, around 36 children were born with a congenital heart disease. The same number for healthy mothers was 8.

Offspring of women with acute pre-gestational complications had a significantly higher heart disease risk than the offspring of women without diabetes complications. The risk for congenital heart disease did not differ by the type of diabetes, as well as the year of birth.

The results of the study suggest that maternal diabetes affects cardiac development in a very early stage of embryo development. Diabetic women looking to get pregnant are advised to treat their diabetes as well as possible.