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. 2025 Aug;103(2):269-276.
doi: 10.1111/cen.15259. Epub 2025 May 4.

Management of Maternal Hypothyroidism in Pregnancy: A Danish Regional Study

Karoline Schack  1 , Line Meyer Laustsen  1 , Randi Ziska Sørensen  1 , Maja Hjelm Lundgaard  1   2 , Nanna Maria Uldall Torp  1   2 , Jesper Karmisholt  2   3 , Stine Linding Andersen  1   2
Affiliations

Management of Maternal Hypothyroidism in Pregnancy: A Danish Regional Study

Karoline Schack et al. Clin Endocrinol (Oxf). 2025 Aug.

Abstract

Objective: Hypothyroidism in pregnant women must be carefully managed to prevent complications. The aim of this study was to evaluate compliance with clinical recommendations for the monitoring and treatment of hypothyroidism in pregnant women and to assess the clinical action upon each biochemical monitoring at different time points in pregnancy.

Design: Retrospective cohort study.

Participants: Pregnant women with known hypothyroidism in the North Denmark Region, 2022-2024, who were managed in the Departments of Endocrinology.

Measurements: Medical records were reviewed for information on biochemical monitoring of thyroid-stimulating hormone (TSH) and Levothyroxine (L-T4) treatment in the pregnancy. The primary study endpoint was the frequency of biochemical monitoring and dose adjustments of L-T4.

Results: Altogether 175 pregnant women with hypothyroidism treated with L-T4 before the pregnancy were studied. Biochemical monitoring of TSH in the pregnancy was performed one to 12 times (median 7 times). When considered until and including the 12th week of pregnancy, the number of women with dose adjustment following biochemical control was 84 of 166 (50.6% (95% CI: 42.7%-58.4%)), whereas from the 13th to 24th week it was 35 of 164 (21.3% (95% CI: 15.3%-28.4%)), and from the 25th week of pregnancy and onwards it was 17 of 165 (10.3% (95% CI: 6.1%-16.0%)).

Conclusion: In a Danish regional cohort of pregnant women with hypothyroidism, biochemical monitoring of thyroid function was often performed and was mostly followed by a change in the dose of L-T4 in early pregnancy ( ~ 50% of the women) and rarely in late pregnancy ( ~ 10% of the women).

Keywords: compliance; gestation; levothyroxine; myxedema; thyrotropin.

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Conflict of interest statement

The authors declare no conflicts of interest.

Figures

FIGURE 1
FIGURE 1
Flowchart of the study inclusion.
FIGURE 2
FIGURE 2
Bar chart illustrating the frequency of having a dose adjustment in ongoing Levothyroxine treatment among women with biochemical assessment of thyroid function. Results are reported as percentage with 95% confidence interval (95% CI) and stratified by sub‐periods of pregnancy (four‐week intervals except for the first period which was counted from the time of ovulation). Numbers in each bar (n/m) indicate the number of women with dose adjustment (n) of all women with biochemical assessment in the defined period (m).
See this image and copyright information in PMC

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