Iwama N, et al. - In this prospective cohort study involving 2,578 pregnant women, researchers assessed the differences in the outcomes of 75-g oral glucose tolerance tests (OGTTs) according to gestational age in Japan using multivariable analysis. Study participants were divided into 3 categories based on their gestational age during the 75-g OGTT: <14 weeks’ gestation, 14–23 weeks’ gestation and 24–32 weeks’ gestation. At the time of the 75-g OGTT, early gestational age was linked to high fasting plasma glucose levels and low corresponding 1-h and 2-h plasma glucose levels. According to findings, the results of the 75-g OGTT differed by gestational age. Using the same 75-g OGTT cut-off values for the diagnosis of gestational diabetes mellitus, irrespective of gestational age, may result in an increase in the incidence of gestational diabetes mellitus in Japan.