INS and obesity due to melanocortin 4 receptor deficiency: To explore metabolic markers that predict changes in insulin sensitivity and glycemic responses earlier in pregnancy, we performed a meal tolerance test (MTT) during the early and late second trimester in an at-risk population.<h4>Methods</h4>We included 30 pregnant women with overweight or obesity in the Pregnancy Outcomes and Maternal Insulin Sensitivity (PROMIS) study.