low tsh and pregnant

[kiki888]

Hi,i am 9 weeks pregnant and on levotiroksin 50 once a day for last five years because of the nodules on tyroid(was also on bromocriptine 2.5 for high prolactine but stoped when got pregnant).I had my first test for tyroid function in 4 weeks of pregnancy and T4 and TSH were normal.Second test was done 4 days ago and only TSH was low,0,1.My gp is not helping,ve been told to do next test in 3 months.The specialist will see me in january but i am not sure what to do with my medicine,is it the right dose,can low tsh harm my baby?Thank you

[Mark Lupo, M.D.]

A slightly low TSH is commonly seen in the first trimester -- even in women not on thyroid medication.  The research suggests that mild hyperthyroidism (ie low TSH) does not have an adverse effect on the baby, whereas mild hypothyroidism (not enought thyroid hormone) can result in problems.  So in most cases, with the situation you describe, we do not make any change but follow the TSH and T4 levels every 4-6 weeks through pregnancy to make sure the medication dose is in the appropriate range.

[Super_sally888]

Hi,

I am also pregnant with hypothyroid.  My endo doesn't monitor TSH during pregnancy, but bases med dose on FT3 and FT4 levels, with target of keeping them high normal range.  We did test my TSH once or twice and it is consistently very low, even when the FT3 and FT4 were only low normal.  

Anyway, we kept adjusting thyroid meds till FT3 and FT4 are high normal range (this involved monthly testing and increase in thyroid meds of 25 mcg every month for the first 6 months.  Latest test was on target and we didn't increase, but we will monitor still...

Don't worry about low TSH.  but do make sure your doc checks the FTs and adjusts meds based on that.

Hope this helps.

[azqtpies]

yes i have hypothyroidism and just had my baby 8 months ago ... do have your tsh monitored as i went up and down throughout my pg! where is a normal tsh #  for you before pg.. try and keep it at that number as i am subclinical hypo meaning i display major symptoms though with lab normal range scale! anything over 1.0 for me my body does not like at all. good luck the baby will be fine! good luck

[kiki888]

Thank you very much.Very helpfull.