Gestational Diabetes Mellitus (GDM) is commonly seen in pregnancy in the Western world. Without proper diagnosis and treatment, it can affect both the mothers health and the fetal outcome. Previous studies have described perinatal risks in such pregnancies and have suggested alterations in organ size in the offspring. Older studies on human fetuses found decreased total weight of the offsprings brain. Thus far not much is known about the intrauterine growth of the human fetal brain under the condition of a diabetic pregnancy.
This study aims to compare the fetal brain volumes from gestational week 27 to 39 from diabetic mothers (case subjects) with healthy controls (control subjects).
Material and Methods
For this prospective case-control-study, pregnant women with either gestational diabetes mellitus or preexisting diabetes mellitus (Type 1 and 2), who received todays standard medical treatment, were assigned one fetal MRT-scan anytime from gestational week 27 to 39 in the department of radiology and nuclear medicine at the General Hospital in Vienna. Included were women with a positive standardized 75 g oral Glucose Tolerance Test (oGTT: fasting 92mg%, 1hour 180mg%, 2 hours153mg%) and subsequently treated with diet or insulin. Further included were pregnant women with previously diagnosed diabetes. Excluded from the study were known maternal or fetal syndromes, children of multiple births or abnormalities detected in the MRT. 52 fetal brainscans were eventually used to measure brain volumes with specific in-house designed software and were then compared to 108 healthy fetuses. The curves were plotted using IBM SPSS 24 and with the help of a covariate analysis the independent influence of the mothers diabetic status on selected brain volumes was determined.
In this study fetuses of diabetic mothers showed larger cortex volumes with an intermediate effect (p < .001 and = .066) compared to controls. The effect was larger if the case subjects were obese (BMI > 30 kg/m). The volume of the white matter, the cerebellum, and the cerebro-spinal fluid were not found to be influenced by the presence of maternal gestational diabetes.
The results coincide with findings that diabetes causes a rise in insulin-like growth factor (IGF I) which in turn causes larger brain cortices in mouse-experiments.