GPT and gestational diabetes: Similarly, elevated ALT levels (≥22 U/L) increased the adjusted OR of maternal overweight/obesity at first antenatal care visit for GDM risk from 2.22 (1.84 to 2.68) to 3.46 (2.79 to 4.29) with significant additive interaction (P < 0.05 for RERI, AP and S).