BMC Pregnancy and Childbirth (Apr 2025)

A prospective study of early pregnancy metal concentrations and gestational diabetes mellitus based on a birth cohort in Northwest China

  • Doudou Zhao,
  • Jie Chen,
  • Xiayang Li,
  • Yishuai Huang,
  • Yu Zhang,
  • Fuyang Zhao,
  • Danmeng Liu,
  • Li Shan,
  • Yang Mi,
  • Lei Shang,
  • Pengfei Qu

DOI
https://doi.org/10.1186/s12884-025-07336-2
Journal volume & issue
Vol. 25, no. 1
pp. 1 – 11

Abstract

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Abstract Background Exposure to metals during early pregnancy may affect maternal glucose metabolism. We were aimed to assess the associations between early pregnancy whole blood concentrations of copper (Cu), zinc (Zn), calcium (Ca), iron (Fe), and magnesium (Mg) with GDM later in the second trimester among pregnant women in Northwest China. Methods This study included 5478 first-trimester pregnant women who participated in the birth cohort of the Northwest Women’s and Children’s Hospital between July 2018 and December 2023. Metal concentrations, basic demographic characteristics, lifestyle and behavior patterns were collected. An oral glucose tolerance test was performed in the second trimester. A generalized linear model was used to analyze the effects of metal concentrations on GDM. A two-piecewise regression model was adopted to examine the threshold effect and find out the turning point. Weighted Quantile Sum (WQS) regression was conducted using a dataset randomly split into training and validation sets at a 4:6 ratio to investigate the association between metal mixtures and GDM. Results Compared to the lowest tertile, the middle (RR = 0.82, 95%CI = 0.71, 0.95) and highest (RR = 0.84, 95%CI = 0.73, 0.97) tertiles of Ca concentrations could decrease the risk of GDM. However, the highest tertile of Cu concentration could increase the risk of GDM (RR = 1.18, 95%CI = 1.01, 1.39). Additionally, a non-linear relationship between Ca concentration with GDM and FPG was observed. The risk of GDM (RR = 0.08, 95%CI: 0.02, 0.31) and FPG (β=-0.56, 95%CI: -0.99, -0.12) decreased with 1 unit increase in ln-transformed Ca concentration below the turning point. However, the WQS index of maternal mixed metals was not correlated with the incidence of GDM (RR = 1.08, 95%CI = 0.98, 1.19). Conclusions Higher Cu concentration during early pregnancy may increase the risk of GDM in mothers. Increased Ca concentration may reduce the risk of GDM and lower the concentration of FPG below the turning point. Our findings could provide an early marker for potentially modifiable risk factors associated with maternal glucose dysregulation during pregnancy.

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