Body fat index: A novel alternative to body mass index for prediction of gestational diabetes and hypertensive disorders in pregnancy.

OBJECTIVES: To evaluate the association of ultrasound measurement of maternal abdominal subcutaneous and pre-peritoneal fat thickness in relation to the subsequent diagnosis of gestational diabetes (GDM), and to assess the association of body fat index (BFI), compared to conventional body mass index (BMI), with respect to the development of some obstetric related complications.

STUDY DESIGN: A prospective study included non-diabetic pregnant women who were scheduled for fetal anatomic survey. Women underwent fat measurements and BFI (pre-peritoneal fat x subcutaneous fat/height) was calculated. They underwent routine glucose screening and diagnostic tests for GDM. Obstetric complications, mode of delivery, and delivery related events were reported. Multivariable logistic regression was used to test potential predictors for development of obesity-related complications. Primary outcome was development of GDM. Secondary outcomes included development of hypertensive disorders during pregnancy and need for cesarean delivery due to labor dystocia. The optimal cut-off points for continuous variables were obtained using a receiver operating characteristic (ROC) curve analyses.

RESULTS: 389 women met study criteria. Median gestational age at time of ultrasound evaluation was 19.1 weeks. Positive family history of diabetes (adjusted odds ratio "OR" 2.30, 95% CI 1.35-3.92), history of GDM (adjusted OR 6.87, 95% CI 3.03-15.61), subcutaneous fat≥13 mm (adjusted OR 4.63, 95% CI 1.60-13.38) and pre-peritoneal fat≥12 mm (adjusted OR 3.32, 95% CI 1.06-10.42) were significant predictors for development of GDM. ROC analysis demonstrated that a BFI > 0.5 was statistically superior to a BMI > 25 or 30 as a predictor of gestational diabetes (adjusted OR 6.24, 95% CI 1.86-20.96). A Similar ROC analysis demonstrated that a BFI > 0.8 was associated with a higher risk for the development of hypertensive disorders of pregnancy (adjusted OR 2.70 [95% CI 1.60-4.55]), and need for cesarean delivery (adjusted OR 2.01[95% CI 1.23-3.28]) than a BMI > 25 or 30.

CONCLUSION: Values obtained by ultrasound measurement of subcutaneous and pre-peritoneal fat are associated with development of GDM and hypertensive disorders in pregnancy. Our data suggest that BFI was a better predictor than BMI for development of GDM and hypertensive disorders in pregnancy and should be studied further.