Gestational diabetes mellitus early prediction by maternal body fat index: A cohort study

To compare the performance of maternal body fat index (BFI) assessed during the first 20+6 weeks among 138 pregnant women in an ultrasound outpatient clinic as a predictor of gestational diabetes mellitus (GDM) later in pregnancy.

Maternal visceral and subcutaneous fat was measured with a convex ultrasound probe placed in two locations on the maternal abdominal surface: the first in the mid-sagittal epigastric region, visualising epigastric fat, and the second 2cm above the maternal umbilical scar, visualising periumbilical fat. Ultrasound callipers measured the distance from dermal edge to the linea alba and after from the linea alba to the anterior hepatic surface (epigastric fat). Periumbilical fat was measured from the dermal edge to the linea alba and after from the linea alba to the anterior aortic surface. The BFI formula was [visceral adipose tissue (mm)×subcutaneous adipose tissue (mm)]/maternal height (cm).

The best thresholds for predicting GDM outcome for epigastric and periumbilical BFI were 1.2 and 4.8, respectively. Odds ratio, sensitivity and specificity were 5.88 (95% CI 1.86-18.6), 80.9%, 58.0% for the epigastric site and 6.31 (95% CI 1.73-22.94), 84.2%, 54.2% for the periumbilical site. Pre-pregnancy body mass index compatible with adult obesity shows inadequate predictive performance for GDM outcome. Only epigastric BFI above 1.2 maintained statistical significance for GDM in the logistic regression analysis, when compared to periumbilical BFI above 4.8.

Epigastric BFI above 1.2 during the first half of pregnancy may help identify women at risk of developing GDM later in pregnancy.