First-Trimester Maternal Serum Zinc-to-Copper Ratio as an Early Biomarker for Gestational Diabetes Mellitus

International Journal of Obstetrics and Gynecology | Vol. 14, No. 9, September 2026 | pp. 1095–1106

DOI: 10.46882/2026/IJOG/000572

Original Research Article

Title: First-Trimester Maternal Serum Zinc-to-Copper Ratio as an Early Biomarker for Gestational Diabetes Mellitus

Names of Authors: Chloe Jenkins¹, Hans-Jürgen Keller²

Authors’ Affiliations:
¹ Department of Obstetrics and Gynaecology, University of Auckland, Auckland, New Zealand
² Department of Obstetrics and Gynecology, Medical University of Graz, Graz, Austria

Abstract:
Trace element homeostasis is essential for normal pancreatic cell function and peripheral glucose clearance. This prospective cohort study investigated the association between first-trimester maternal serum zinc (Zn) and copper (Cu) concentrations and the subsequent development of Gestational Diabetes Mellitus (GDM). Serum samples were collected from 600 normotensive nulliparous women between 11 and 13⁺⁶ weeks of gestation, and absolute mineral levels were quantified via inductively coupled plasma mass spectrometry. All participants underwent standard 2-hour, 75 g oral glucose tolerance testing at 24 to 28 weeks to diagnose GDM. Fifty-eight women (9.7%) developed GDM. First-trimester maternal serum zinc levels were significantly lower (58.4 ± 11.2 μg/dL vs. 74.6 ± 14.5 μg/dL, p < 0.001) and copper levels were significantly higher in the group that developed GDM compared to normoglycemic controls. Consequently, the mean serum Zn/Cu ratio was significantly depressed in the GDM cohort (0.42 ± 0.12 vs. 0.78 ± 0.18, p < 0.001). Adjusting for maternal age, family history, and body mass index, multivariable logistic regression modeling confirmed that a first-trimester Zn/Cu ratio < 0.50 was independently associated with a fourfold increase in GDM development risk (Odds Ratio = 4.12; 95% CI, 2.15 to 7.84, p < 0.001). A depressed maternal zinc-to-copper ratio during the first trimester serves as a highly sensitive, early metabolic biomarker for gestational diabetes mellitus.

Keywords: Gestational Diabetes Mellitus; Zinc; Copper; Zn/Cu Ratio; Trace Elements; First-Trimester Screening.

Manuscript Timeline: Received: July 20, 2026; Revised: September 08, 2026; Accepted: September 20, 2026; Published: September 28, 2026.

Citation: Jenkins C, Keller HJ. First-Trimester Maternal Serum Zinc-to-Copper Ratio as an Early Biomarker for Gestational Diabetes Mellitus. International Journal of Obstetrics and Gynecology. 2026; 14(9): 1095–1106.

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