In summary, our research has shown PAPP-A to be a significant predictor of third-trimester obesity risk in pregnancies without complications (OR = 0.53; C.I. at 95%: 0.39–0.66; p = 0.04 in the single-variant study (Table 4); OR = 0.58; C.I. at 95%: 0.29–0.93; p = 0.074 in the multi-variant analysis) (Table 5). Here, PAPPA is linked to obesity due to melanocortin 4 receptor deficiency.