Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2022 Feb;96(2):263-269.
doi: 10.1111/cen.14488. Epub 2021 May 10.

Weight-based thyroid dosing vs fixed dosing during pregnancy for subclinical hypothyroidism: A retrospective cohort study

Balsam Bohlega  1 , Afshan Zahedi  1   2 , George Tomlinson  1   3 , Denice S Feig  1   4   5
Affiliations

Weight-based thyroid dosing vs fixed dosing during pregnancy for subclinical hypothyroidism: A retrospective cohort study

Balsam Bohlega et al. Clin Endocrinol (Oxf). 2022 Feb.

Abstract

Objective: Thyroid hormones play a crucial role in foetal growth and neurocognitive development. Our aim was to compare a weight-based dosing method of starting thyroxine to a fixed-dose method in newly diagnosed women with subclinical hypothyroidism during pregnancy.

Design: We performed a retrospective cohort study of consecutive women with newly diagnosed subclinical hypothyroidism during pregnancy seen at Mount Sinai Hospital and Women's College Hospital, Toronto, Canada 2015-2018.

Patients: We identified women that were treated based on pre-pregnancy weight and those that were given a fixed dose of 50 mcg/day.

Measurements: The percent of women who reached the target TSH of <2.5 mIU/L within 4-8 weeks was compared using a chi-squared test and a logistic regression model, adjusting for age, initial TSH and gestational age treatment was started.

Results: 393 women were included: 252 treated using a fixed-dose approach; 141 treated based on pre-pregnancy weight. In the unadjusted analysis, there was no difference between the groups in the percentage of women in the target range within 4-8 weeks (89.6% in the fixed-dose group vs 88.8% in the weight-based group (p = .954)). However, after adjustment for between-group differences in age, initial TSH and gestational age treatment was started, there was a significantly greater odds of achieving the target range using the weight-based dosing (OR 4.26 (1.60-11.7), p = .004).

Conclusions: Treating women with newly diagnosed subclinical hypothyroidism during pregnancy with a weight-based strategy increased the odds of reaching the target TSH range within 4-8 weeks. Clinicians caring for these women should consider this approach when starting treatment during pregnancy.

Keywords: hypothyroidism; pregnancy; subclinical hypothyroidism; thyroid; thyroxine.

PubMed Disclaimer

References

REFERENCES

    1. Huget-Penner S, Feig DS. Maternal thyroid disease and its effects on the fetus and perinatal outcomes. Prenat Diagn. 2020;40(9):1077-1084.
    1. Jansen TA, Korevaar TIM, Mulder TA, et al. Maternal thyroid function during pregnancy and child brain morphology: a time window-specific analysis of a prospective cohort. Lancet Diabetes Endocrinol. 2019;7(8):629-637.
    1. Allan WC, Haddow JE, Palomaki GE, et al. Maternal thyroid deficiency and pregnancy complications: implications for population screening. J Med Screen. 2000;7(3):127-130.
    1. Casey BM, Dashe JS, Wells CE, et al. Subclinical hypothyroidism and pregnancy outcomes. Obstet Gynecol. 2005;105(2):239-245.
    1. Rovet JF. The role of thyroid hormones for brain development and cognitive function. Endocr Dev. 2014;26:26-43.

LinkOut - more resources