INTRODUCTION: The risk of congenital heart defects in the offspring of women with Type 2 diabetes is only sparsely described. The aim of this review was to estimate the prevalence of congenital heart defects in offspring of women with Type 2 diabetes in comparison to offspring of women with Type 1 diabetes and to offspring of the background population.

METHODS: This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. A literature search was performed in the PubMed, Embase and Cochrane databases. Studies were included if they were published from 2007 to 2018, comprised a minimum of 200 offspring of women with Type 2 diabetes and examined the prevalence of congenital heart defects.

RESULTS: Five cohort studies with a total of 23,845 offspring of women with Type 2 diabetes were included. The studies were heterogeneous with respect to method of diagnosis and whether terminated pregnancies were included, and a meta-analysis could not be performed. The mean prevalence of congenital heart defects was 44 (range: 26-65) per 1,000 offspring. The mean relative risk was 0.82 (range: 0.53-1.01) compared with offspring of women with Type 1 diabetes, and 3.83 (range: 2.53-5.49) compared with the background population. A positive association was described between the prevalence of congenital heart defects and the maternal glycated haemoglobin level, but not with medical treatment.

CONCLUSIONS: The risk of congenital heart defects among offspring of women with Type 2 diabetes was comparable to that of offspring of women with Type 1 diabetes and almost four times higher than in the background population.