To observe the pressure level and hair cortisol level of pregnant women, and explore the influence of pregnancy stress on gestational diabetes mellitus(GDM) and underlying mechanism.

The eligible pregnant women at People′s Hospital of Henan Province from January 2020 to December 2021 were selected. Pregnancy stress scale(PSS) was used for stress assessment at 10^th-12^th gestational weeks. The hair of pregnant women was collected to detect cortisol at 24^th-28^th gestational weeks. Oral glucose tolerance test was performed at the 24^th, 28^th, 32^nd and 36^th gestational weeks to diagnose GDM. The endpoint event of follow-up was GDM.

Among 498 pregnant women, 20(4.0%) had no stress, 321(64.5%) had mild stress, 128(25.7%) had moderate stress, and 29(5.8%) had severe stress. There was a significant positive correlation between maternal hair cortisol levels and the total PSS score. The hair cortisol level in severe stress group was significantly higher than that in other groups, and the hair cortisol level in GDM group was significantly higher than that in non-GDM group. There were significant differences in GDM-free survival curves among different stress groups(χ²=15.975, P=0.001). Cox multivariate regression showed that severe stress was an independent risk factor for GDM. The area under the receiver operating characteristic curve is 0.747(95%CI 0.545-0.950, P=0.028).

Severe stress during pregnancy is an independent risk factor for the occurrence of GDM, and has a certain ability to predict GDM. Cortisol may play a role in the process through which stress mediates GDM. For pregnant women experiencing severe stress, it is necessary to assess stress levels dynamically and take measures accordingly.

Pregnancy; Stress; Cortisol; Gestational diabetes mellitus