Significant thresholds for the 75-g oral glucose tolerance test in pregnancy

Abstract

The significant threshold values for the 75-g oral glucose tolerance test (oGTT) during pregnancy have yet to be conclusively determined. This study aimed to identify the risk significance of various set thresholds for the oGTT result. Women undergoing a 75-g oGTT during the third trimester of pregnancy were classified into three groups: mild gestational impaired glucose tolerance (GIGT; 2-h postload glucose, 8.0–8.5 mmol/l; n=75), moderate-severe GIGT (8.6–10.9 mmol/l; n=167), and GDM (≥11.0 mmol/l; n=76). Outcome indicators of these three groups of women were compared to the parameters of the women with a presumed normal carbohydrate metabolism ( n=12,185). The results show that with increasing oGTT thresholds, there was an increasing risk of maternal morbidity in the form of hypertensive disorders complicating pregnancy, as well as obstetric intervention such as induction of labor, cesarean delivery, and preterm delivery. The infant was also at increasing risk with increasing oGTT thresholds from respiratory distress, macrosomia, and associated shoulder dystocia. It would appear, therefore, that abnormal glucose tolerance in pregnancy, even as defined by the World Health Organization criteria, has proportionate risks to both mother and child.