Treated overt hypothyroidism is associated with higher diabetes treatment requirements in gestational diabetes: a three-group prospective study

Meryem Keçeci Oğuzhanoğlu; Senem Karacabey Çakmak

doi:10.38053/acmj.1957626

Treated overt hypothyroidism is associated with higher diabetes treatment requirements in gestational diabetes: a three-group prospective study

Abstract

Aims: Whether levothyroxine replacement normalizes diabetes management in gestational diabetes mellitus (GDM) with co-existing hypothyroidism is unclear. We compared treatment requirements, glycemic control, lipid profile, and vitamin D status across GDM alone, GDM with treated hypothyroidism, and hypothyroidism alone. Methods: Prospective three-group cohort study of 240 pregnant women (80/group) assessed once at 24-28 weeks; hypothyroid patients were on stable levothyroxine (≥12 weeks). Groups were compared with Kruskal-Wallis/Chi-square tests (Bonferroni-corrected); the primary outcome was modeled by multivariable logistic regression (age, body-mass index, baseline glucose, gestational age). Results: Thyroid-stimulating hormone was higher in GDM+hypothyroidism than GDM-alone (1.99 vs. 1.51 μIU/ml; p=0.004). Lipid parameters did not differ between groups (all p>0.3). Diet therapy controlled glycemia in 22.5% of GDM+hypothyroidism versus 50.0% of GDM-alone; pharmacologic treatment was required in 77.5% versus 50.0% (p<0.001), persisting after adjustment (confidence interval 3.65, 95% confidence interval 1.58-8.39, p=0.002). Vitamin D was lower in both GDM groups than hypothyroidism-alone (p=0.003, p<0.001) but similar between the two GDM groups (p=0.484), arguing against an additive effect of co-existing GDM and hypothyroidism. Homeostasis Model Assessment for Insulin Resistance and insulin were higher in both GDM groups than hypothyroidism-alone (p<0.001, p=0.002) but similar between them (p=1.00), consistent with GDM driving insulin resistance. Hemoglobin A1c (HbA1c) did not differ across groups (p=0.089). Conclusion: Treated overt hypothyroidism was associated with higher pharmacologic treatment requirements in GDM, independent of confounders. Lipid parameters and HbA1c did not differ between groups; vitamin D was lower in both GDM groups without evidence of an additive effect. These findings identify GDM with treated hypothyroidism as a higher-risk subgroup warranting closer monitoring, pending confirmation in larger trials.

Keywords

Supporting Institution

This research received no specific grant or financial support from any funding agency in the public, commercial, or not-for-profit sectors.

Ethical Statement

This study was approved by the Institutional Ethics Committee of Haseki Training and Research Hospital, University of Health Sciences (Protocol No: 327-2025, Approval Date: December 17, 2025). The study was conducted in accordance with the Declaration of Helsinki and its later amendments. Written informed consent was obtained from all participants.

Thanks

The authors thank all the pregnant women who participated in this study, as well as the nursing, laboratory, and clinical staff of Haseki Training and Research Hospital for their valuable assistance with patient recruitment, sample collection, and data management throughout the study period.

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Details

Primary Language

English

Subjects

Endocrinology

Journal Section

Research Article

Authors

Meryem Keçeci Oğuzhanoğlu ^*
0009-0004-7614-2440
Türkiye

Senem Karacabey Çakmak This is me
0000-0003-0987-740X
Türkiye

Publication Date

September 11, 2026

Submission Date

May 23, 2026

Acceptance Date

July 18, 2026

Published in Issue

Year 2026 Volume: 8 Number: 5

DOI

https://doi.org/10.38053/acmj.1957626

IZ

https://izlik.org/JA42FC95EW

Cite

RIS / Bibtex

APA

Keçeci Oğuzhanoğlu, M., & Çakmak, S. K. (2026). Treated overt hypothyroidism is associated with higher diabetes treatment requirements in gestational diabetes: a three-group prospective study. Anatolian Current Medical Journal, 8(5), 853-861. https://doi.org/10.38053/acmj.1957626

AMA

1.Keçeci Oğuzhanoğlu M, Çakmak SK. Treated overt hypothyroidism is associated with higher diabetes treatment requirements in gestational diabetes: a three-group prospective study. Anatolian Curr Med J / ACMJ / acmj. 2026;8(5):853-861. doi:10.38053/acmj.1957626

Chicago

Keçeci Oğuzhanoğlu, Meryem, and Senem Karacabey Çakmak. 2026. “Treated Overt Hypothyroidism Is Associated With Higher Diabetes Treatment Requirements in Gestational Diabetes: A Three-Group Prospective Study”. Anatolian Current Medical Journal 8 (5): 853-61. https://doi.org/10.38053/acmj.1957626.

EndNote

Keçeci Oğuzhanoğlu M, Çakmak SK (September 1, 2026) Treated overt hypothyroidism is associated with higher diabetes treatment requirements in gestational diabetes: a three-group prospective study. Anatolian Current Medical Journal 8 5 853–861.

IEEE

[1]M. Keçeci Oğuzhanoğlu and S. K. Çakmak, “Treated overt hypothyroidism is associated with higher diabetes treatment requirements in gestational diabetes: a three-group prospective study”, Anatolian Curr Med J / ACMJ / acmj, vol. 8, no. 5, pp. 853–861, Sept. 2026, doi: 10.38053/acmj.1957626.

ISNAD

Keçeci Oğuzhanoğlu, Meryem - Çakmak, Senem Karacabey. “Treated Overt Hypothyroidism Is Associated With Higher Diabetes Treatment Requirements in Gestational Diabetes: A Three-Group Prospective Study”. Anatolian Current Medical Journal 8/5 (September 1, 2026): 853-861. https://doi.org/10.38053/acmj.1957626.

JAMA

1.Keçeci Oğuzhanoğlu M, Çakmak SK. Treated overt hypothyroidism is associated with higher diabetes treatment requirements in gestational diabetes: a three-group prospective study. Anatolian Curr Med J / ACMJ / acmj. 2026;8:853–861.

MLA

Keçeci Oğuzhanoğlu, Meryem, and Senem Karacabey Çakmak. “Treated Overt Hypothyroidism Is Associated With Higher Diabetes Treatment Requirements in Gestational Diabetes: A Three-Group Prospective Study”. Anatolian Current Medical Journal, vol. 8, no. 5, Sept. 2026, pp. 853-61, doi:10.38053/acmj.1957626.

Vancouver

1.Meryem Keçeci Oğuzhanoğlu, Senem Karacabey Çakmak. Treated overt hypothyroidism is associated with higher diabetes treatment requirements in gestational diabetes: a three-group prospective study. Anatolian Curr Med J / ACMJ / acmj. 2026 Sep. 1;8(5):853-61. doi:10.38053/acmj.1957626