Risk of adverse pregnancy outcomes in pregnant women with gestational diabetes mellitus by age: a multicentric cohort study in Hebei, China.

Gestational diabetes mellitus (GDM) is an unique metabolic disorder that occurs during pregnancy. Both GDM and advanced age increase the risk of adverse pregnancy outcomes. This study used a GDM cohort study to investigate the role of age in the adverse pregnancy outcomes for pregnant women with GDM. From 2015 to 2021, 308,175 pregnant women were selected, and the data received from 22 hospitals by the Hebei Province Maternal Near Miss Surveillance System. There were 24,551 pregnant women with GDM that were divided into five groups by age (20-24, 25-29, 30-34, 35-39, 40-44 years old). Because the prevalence of adverse pregnancy outcomes was lower in pregnant women with GDM aged 25-29, they were used as a reference group (P < 0.05). Compared with GDM women aged 25-29 years, GDM women aged 35-44 years had a significant higher risk of cesarean delivery (aOR: 2.86, 95% CI 2.52-3.25) (P < 0.001), abnormal fetal position (aOR: 1.78, 95% CI 1.31-2.37) (P < 0.001), pre-eclampsia (aOR: 1.28, 95% CI 1.01-1.61) (P < 0.05), macrosomia (aOR: 1.25, 95% CI 1.08-1.45) (P < 0.05), and large for gestational age (LGA) (aOR: 1.16, 95% CI 1.02-1.31) (P < 0.05), GDM women aged 40-44 years had a higher risk of placenta previa (aOR: 2.53, 95% CI 1.01-6.35) (P < 0.05), anemia (aOR: 3.45, 95% CI 1.23-9.68) (P < 0.05) and small for gestational age (aOR: 1.32, 95% CI 1.01-1.60) (P < 0.05). Advanced maternal age was an independent risk factor for abnormal fetal position, pre-eclampsia, anemia, macrosomia, and LGA in pregnant women with GDM.