Pregnant and TSH gone from too high to too low ... - Thyroid UK

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Pregnant and TSH gone from too high to too low in 4 weeks

Kinney1 profile image

I had my TSH levels checked a month ago when I was 6 weeks pregnant and they were 2.09. I had my thyroxine dose increased from 100mg to 125mg.

Because I'm seeing the endocrinologist tomorrow, I had a blood test and have just had the results back - I've dropped to 0.09.

I'm really worried about this, can this plunge from hypo to hyper hurt the baby?

Obviously this will be the focus of my appointment with the endocrinologist tomorrow but wondered if anyone has any wisdom to offer today?

Thank you in advance

8 Replies

Do you have any results for Free T4 and Free T3 (complete with reference ranges)? They are more important and more informative than TSH.

Kinney1 profile image
Kinney1 in reply to humanbean

Of course -

Thyroid function test

Serum free T4 level 21.7 pmol/L [11.0 - 26.0]

Serum TSH level 0.09 mU/L [0.27 - 4.2]

Outside reference range

humanbean profile image
humanbean in reply to Kinney1

If you are hypothyroid you cannot become hyperthyroid. You can be over-medicated though.

Your Free T4 is 71% of the way through the range. For many people this level of Free T4 is absolutely fine and they feel quite well on it. There is no justification for reducing your dose based on this level of Free T4.

Unfortunately, the most informative result would have been a Free T3, which is the active hormone, and yours wasn't tested. If it was over the range you may have been over-medicated and a small reduction in your dose would have been justified. Since you don't know your Free T3 any change of dose is a jump into the dark.

Based on what I read on here every day your endo is likely to insist that you reduce your dose. Don't agree to go back to your previous dose because you know that was too little. At most you should agree to a reduction to 100 and 125mcg on alternate days.

Have you developed any symptoms of over-medication?

Edit : In your shoes I wouldn't be happy about reducing dose at all. I am being pragmatic though, in suggesting you agree to a small reduction.

Kinney1 profile image
Kinney1 in reply to humanbean

Thanks for your response, humanbean.

It's hard to say if I have been feeling any effects of over medication as I have been overwhelmed by early pregnancy symptoms.

I suppose my main worry was that I have inadvertently caused damage to my baby's development.

humanbean profile image
humanbean in reply to Kinney1

TSH is not important in terms of your baby's development. It is your Free T4 and Free T3 which matter until such time as your baby's own thyroid is fully developed. And your Free T4 being 71% of the way through the range is absolutely fine.

Kinney1 profile image
Kinney1 in reply to humanbean

Thank you, that is very reassuring.

If you want your own records of thyroid function and nutrients (which can be reduced in many hypothyroid people), you can buy your own tests privately.

The most popular tests on this forum are :

If you want to just test the very basic thyroid levels :

Notice that you can get 10% off Medichecks tests with this discount code :

On Thursdays there are often other special offers which give more money off. You can't combine offers though.

How did this go in the end ?

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