Background:Maternal type 1 diabetes mellitus (DM) is a recognised risk factor for the development of fetal
congenital heart disease (CHD). However the risk of CHD in babies of women with gestational diabetes mellitus (GDM)
is less well known.
Objectives:The aim of this 10 year, retrospective, observational study was to compare the occurrence of
congenital heart disease in these two referral groups and to evaluate whether detailed fetal echocardiography should
be offered to women with GDM.
Results:During the study period 1401 women with type 1 DM were referred for fetal echocardiography and a fetal
congenital heart defect was diagnosed in 44 cases (3.1%). In the GDM cohort 543 women were referred for screening
and 15 cases (2.76%) of fetal CHD were detected.
Conclusions: Based on our data we consider women with GDM to be at an increased risk of having a baby
with CHD. This risk might be due to a combination of hyperglycaemia, insulin resistance, an elevated BMI and more
importantly, undiagnosed pre-gestational diabetes. Until more detailed data from larger studies is available, we will
continue to accept these women as referrals for detailed fetal echocardiography.