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

Area of Science:

• Obstetrics and Gynecology
• Endocrinology
• Maternal-Fetal Medicine

Background:

• Thyroid hormones are vital for fetal development and neurocognition.
• Subclinical hypothyroidism in pregnancy requires careful management to optimize maternal and fetal outcomes.

Purpose of the Study:

• To compare the efficacy of weight-based versus fixed-dose thyroxine initiation in pregnant women with newly diagnosed subclinical hypothyroidism.
• To determine which dosing strategy more effectively achieves target thyroid-stimulating hormone (TSH) levels.

Main Methods:

• Retrospective cohort study of 393 women with newly diagnosed subclinical hypothyroidism during pregnancy.
• Comparison of women treated with weight-based dosing versus a fixed 50 mcg/day dose.
• Analysis using chi-squared test and logistic regression, adjusting for age, initial TSH, and gestational age at treatment initiation.

Main Results:

• No significant difference in achieving target TSH (<2.5 mIU/L) within 4-8 weeks in unadjusted analysis (89.6% fixed-dose vs. 88.8% weight-based).
• Adjusted analysis revealed significantly higher odds of reaching the target TSH range with weight-based dosing (OR 4.26, p=0.004).
• Weight-based dosing demonstrated superior efficacy in achieving therapeutic TSH levels after accounting for confounding factors.

Conclusions:

• Weight-based thyroxine dosing is a more effective strategy for initiating treatment in pregnant women with subclinical hypothyroidism.
• This approach increases the likelihood of achieving target TSH levels within 4-8 weeks of treatment initiation.
• Clinicians should consider weight-based dosing for improved management of subclinical hypothyroidism during pregnancy.