Adv Lab Med. 2026 Apr 28;7(2):132-139. doi: 10.1515/almed-2026-0007. eCollection 2026 Jun.
ABSTRACT
OBJECTIVES: Gestational diabetes mellitus (GDM) and thyroid dysfunction are two common endocrine diseases during pregnancy, both of which can adversely affect maternal and fetal health. Numerous studies have shown that abnormalities in thyroid hormones, particularly TSH and FT4, are associated with an increased risk of developing gestational diabetes. However, current research results are inconsistent due to differences in race, geographic location, and testing reference thresholds. This study aimed to evaluate the early predictive value of first-trimester thyroid stimulating hormone (TSH) and free thyroxine (FT4) levels for the development of GDM.
METHODS: A retrospective cohort study was conducted on 272 pregnant women from December 2023 to March 2025. Participants meeting inclusion criteria had TSH and FT4 levels measured in the first trimester (9-13 weeks) and underwent a 75 g oral glucose tolerance test between 24 and 28 weeks of gestation.
RESULTS: FT4 concentrations were significantly lower in the GDM group compared to the non-GDM group, whereas TSH levels showed no significant difference. An FT4 cut-off of ≤1.17 ng/dL predicted GDM with an area under the curve (AUC) of 0.715, a sensitivity of 86.5 %, and a specificity of 52.3 %. Multivariate logistic regression identified FT4≤1.17 ng/dL and pre-pregnancy body mass index BMI≥23 kg/m2 as independent risk factors associated with GDM.
CONCLUSIONS: Low first-trimester FT4 levels are significantly associated with an increased risk of GDM. FT4 may serve as a valuable early predictive biomarker, suggesting a potential role for thyroid function screening in early pregnancy to optimize risk stratification.
PMID:42136982 | PMC:PMC13169816 | DOI:10.1515/almed-2026-0007