How to deal with low TSH levels during pregnancy?

Question

Hi doctor,

I am a thyroidectomy patient on Levothyroxine 150 mg and five months pregnant. Last month my thyroid T4 levels were normal, and my TSH levels were low at 0.248. My endocrinologist said it was fine. However, my gynecologist took blood work again this month, and T4 is still normal, but TSH levels are even lower at 0.038. Does my endocrinologist have to adjust my medication dosage? And is this low level of TSH going to affect the baby?

Answer 1

Hi,

Welcome to icliniq.com.

Do you have thyroid cancer? If yes, mention the type, stage, previous treatments, attach recent TG (thyroglobulin) or TG ab (thyroglobulin antibody), and USG (ultrasonogram results). How much do you weigh? What was your pre-pregnancy dose? Answering these questions will help me to guide you better. Slightly suppressed TSH (thyroid stimulating hormone) level will usually not affect the baby.

Answer 2

Hi,

Welcome back to icliniq.com.

I have to take it as you had papillary thyroid cancer, an initial intermediate risk (kindly attach if you have the pre-operative scan and operative pathology results), so you underwent surgery, and radioiodine remnant ablation. I do not know what your subsequent response was. Whether thyroglobulin was undetectable, ultrasound or whole body iodine scan showed no residual thyroid tissue or nodes. If possible, please send those results. Anyways, the TSH (thyroid stimulating hormone) goal for you is between 0.5 and 2.0 mIU/mL or 0.1 and 0.5 mIU/mL. It is very unlikely that it is less than 0.1 mIU/mL. So I recommend decreasing the Levothyroxine dose to 125 mcg. Repeat TSH (thyroid stimulating hormone) in six weeks. But do not worry. The very low TSH (thyroid stimulating hormone) will not affect your baby.