BackgroundPregnant women with gestational diabetes mellitus (GDM) often have an increased risk of adverse pregnancy outcomes. The purpose of this study was to explore the prevalence and characteristics of GDM in Xi’an from 2015 to 2021 since the implementation of China’s “Two-Child policy” and to provide a clinical basis for the management of GDM.MethodsWe analyzed the oral glucose tolerance test (OGTT) results of 152,836 pregnant women who underwent routine prenatal examination at the Northwest Women and Children’s Hospital from 2015 to 2021. Additionally, we analyzed the GDM prevalence and characteristics.ResultsThe prevalence of GDM in the Xi’an urban area was 24.66% and exhibited an increasing trend annually (χ2 for trend = 43.922, p < 0.001) and with age (χ2 for trend = 2527.000, p < 0.001). Consistent with this, the proportion of pregnant women aged 18–25 and 26–30 years decreased significantly with the annual growth (χ2 for trend = 183.279, p < 0.001 and χ2 for trend = 33.192, p < 0.001, respectively). The proportion of pregnant women aged 31–35 and 36–42 years increased gradually annually (χ2 for trend = 134.436, p < 0.001and χ2 for trend = 44.403, p < 0.001, respectively). Of the pregnant women diagnosed with GDM, 71.15% (65.05–74.95%) had abnormal fasting plasma glucose (FPG) values. The highest percentage of patients had a single abnormal OGTT value (68.31%; 65.77–70.61%), followed by two (20.52%; 18.79–22.55%) and three (11.17%; 10.11–11.85%) abnormal values (FPG and 1-h and 2-h plasma glucose (PG).ConclusionThe prevalence of GDM among pregnant women in Xi’an region was high, and it had a increasing trend over the period from 2015 to 2021. Notably, the proportion of elder pregnant women, aged 31–42 years, presented a significant rise after the implementation of the universal two-child policy. On the basis of the high incidence of GDM among elder pregnant women and the high rate of abnormal OGTT values (numbe ≥ 2) in pregnant women diagnosed with GDM, the management of GDM should be intensified, and relevant departments should pay more attention to pregnant women of advanced age.