From the Guidelines
Cytomel (liothyronine) is not recommended as a first-line treatment during pregnancy, and levothyroxine is the preferred choice. This recommendation is based on the guidelines for the management of subclinical thyroid disease, which suggest that levothyroxine should be used to treat pregnant women with elevated serum TSH levels to restore the serum TSH concentration to the reference range 1. The potential benefits of levothyroxine therapy in pregnancy, including reducing the risk of fetal wastage and subsequent neuropsychological complications in the offspring, outweigh the risks, which are minimal when the treatment is appropriately managed 1.
Some key points to consider when managing thyroid conditions during pregnancy include:
- Monitoring serum TSH concentration every 6 to 8 weeks during pregnancy and modifying the levothyroxine dose as needed 1
- Continuing necessary thyroid medication with careful monitoring, as untreated thyroid disorders can pose greater risks to both mother and baby than properly managed medication
- Maintaining TSH levels within the pregnancy-specific reference ranges, which are generally lower than non-pregnant ranges
- Making any adjustments to thyroid medication during pregnancy only under medical supervision
It is essential for women who are already taking Cytomel for thyroid conditions before becoming pregnant to consult with their healthcare provider to discuss the best course of treatment during pregnancy. The healthcare provider may recommend switching to levothyroxine or continuing with Cytomel under close monitoring, depending on the individual case.
From the FDA Drug Label
Pregnancy Category A Thyroid hormones do not readily cross the placental barrier. The clinical experience to date does not indicate any adverse effect on fetuses when thyroid hormones are administered to pregnant women On the basis of current knowledge, thyroid replacement therapy to hypothyroid women should not be discontinued during pregnancy.
Cytomel (liothyronine) is recommended to continue during pregnancy if the patient is already on thyroid replacement therapy, as the clinical experience does not indicate any adverse effect on fetuses when thyroid hormones are administered to pregnant women 2.
From the Research
Cytomel Use During Pregnancy
- Cytomel, also known as liothyronine, is a medication used to treat hypothyroidism.
- The use of liothyronine during pregnancy is a topic of debate, with some studies suggesting that it may be necessary for certain patients, while others recommend caution due to potential risks to the fetus 3.
- A study published in 2015 discussed the theoretical dangers of combination levothyroxine and liothyronine treatment during pregnancy, highlighting the need for careful consideration and monitoring of thyroid replacement therapy in pregnant women 3.
- Another study published in 2023 provided guidance on the use of liothyronine for hypothyroidism, but noted that this guidance is focused on non-pregnant adults and may not be directly applicable to pregnant women 4.
- There is limited research specifically addressing the use of Cytomel during pregnancy, and more studies are needed to fully understand its safety and efficacy in this population.
- In general, medications should be used during pregnancy only when absolutely necessary, and under the close supervision of a healthcare provider 5, 6.
- A randomized controlled trial published in 2003 found that combination therapy with levothyroxine and liothyronine did not provide significant benefits over levothyroxine monotherapy for patients with primary hypothyroidism, but this study did not specifically address pregnancy 7.