Assessment of fetal thymus size and BMI in pregnant women with diabetes

Materials and methods: The study group consisted of 63 pregnant women admitted to the Department of Perinatology, Obstetrics and Gynaecology. Inclusion criteria included patients with PGDM – 11 pregnancies, GDM1– 23 pregnancies, and GDM2 – 29 pregnancies. Exclusion criteria included pregnant women with gestational diabetes and history of other comorbidities as well as multiple pregnancies, fetal developmental abnormalities and genetic disorders. Each patient received a detailed fetal ultrasound performed by the team of ultrasound experts specialising in obstetric ultrasonography. Fetal thymus measurements were obtained between 14+5 and 40+0 weeks of gestational age. After the three-vessel view was clearly displayed we assessed longitudinal dimensions of the thymus. The obtained measurements were juxtaposed with nomograms for thymus size in healthy foetuses whose mothers had no history of diabetes. Prior to ultrasound examination the participants were asked to complete a questionnaire regarding their body weight status before 10 weeks of gestational age. Results: The Mann–Whitney U test was used for comparison of two groups, i.e. diabetic pregnancies and non-diabetic pregnancies, whereas Kruskal–Wallis H test was used to compare multiple groups. A linear regression model was used to determine the correlation between the type of diabetes and fetal thymus size as well as between maternal BMI and fetal thymus size. The significance level α was set at 0.05. Thymus size is statistically smaller in foetuses of diabetic mothers when compared to healthy controls. Overweighted and obese pregnancy is not a factor affecting fetal thymus size.