Appropriate neck/waist circumference cut-off points for gestational diabetes prediction in Iranian pregnant women: The baseline analysis of the Qazvin maternal and neonatal metabolic study (QMNMS), Iran

Abstract

BackgroundGestational diabetes is the most common complication during pregnancy and it is essential to identify the high-risk groups for gestational diabetes mellitus (GDM) in the first trimester. A large neck circumference (NC) in the first trimester is a measure of obesity. ObjectiveThe present study investigated whether pregnant women's first-trimester NC and waist circumference (WC) measurements present a predictive index for GDM diagnosis. Materials and methodsThis longitudinal cohort study was conducted on 676 pregnant women aged ≥20 years. Pregnant women at 12–14th (baseline) gestational weeks underwent measurement of neck and other anthropometric indices. GDM was diagnosed with 75-g oral glucose tolerance test at 24–28th gestational week. ResultsGDM was developed in 110 (16.3%) pregnant women. The logistic regression analysis showed that baseline NC > 33.5 cm (OR: 2.037, 95% CI: 1.313–3.161; P = 0.002) and WC > 90.5 (OR: 2.299, 95% CI: 1.510–3.501; p < 0.001) were independent predictors of GDM. The area under the receiver operating characteristic (ROC) curve analysis of baseline NC and WC for GDM prediction respectively yielded 0.614 (95% CI: 0.558–0.670, p < 0.001) and 0.641 (CI: 0.583–0.698, p < 0.001). The optimal cut-off level of maternal baseline NC was >33.5 cm, with 68.5% sensitivity and 48.3% specificity, and for baseline WC it was >90.5.50 cm, with 57% sensitivity and 63.4% specificity. ConclusionPregnant women with an NC > 33.5 cm and a WC > 90.5 cm at baseline (12–14th gestational weeks) had a higher chance of developing GDM. first-trimester NC and waist circumference (WC) measurements present a predictive index for GDM diagnosis.