Thyroid UK
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Thyroidectomy and breastfeeding hormones


I'm a breastfeeding mum to a 1 year old. I had a total thyroidectomy over ten years ago and have been on a surpressive dose of levothyroxine since. Since breastfeeding I have been feeling hyperthyroid symptoms. Is there a link between reduced oestrogen levels in breastfeeding and the effect this has on thyroid hormone uptake? My blood levels haven't changed dramatically.

Any advice/experiences appreciated.

8 Replies

I'm sorry you're not feeling to good at present, particularly with a 1 year old to care for.

Can you get a copy of your blood test results from the surgery with the ranges and post for comments (put on a new question if you don't have them to hand).

Maybe it's time for a reappraisal of your thyroid hormone replacements. There's been research which says the addition of T3 can be helpful (not only for those who have had a TT).

If you've not had a recent blood test make an appointment for the earliest and fast (you can drink water). Leave approx 24 hours between your last dose of levo and the test.

Also ask for a FT4 and Free T3 test as well as the usual ones. We have to convert to sufficient T3 from the T4 (levo) and sometimes cannot which means we could feel unwell. Also request B12, Vit D, iron, ferritin and folate as we can be deficient which can also cause symptoms.

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Thank you both for your responses. I've been to the GP this morning and had some results back.

my levels have actually dropped a bit, which really surprised me!

June results:

Ft4 - 0.31

Results from Tuesday;

Ft4- 17.0

Tsh 1.14

Ecg normal, 9am cortisol normal, b12 iron etc all normal.

My periods have returned, which implies my oestrogen levels must have risen since June.

Thyroid specialist says my symptoms don't sound thyroid related.

GP has recommended raising my thyroxine by 25mg to see if it helps (mainly as no other clues!!)

Any idea?




Ranges for ft4:


Ranges for tsh:


I've always been way up in the higher end of the ranges as have always been suppressed because it was cancer. 17 is actually quite low for me...


I'm guessing you are on a TSH suppressive dose of levothyroxine because you had thyroid cancer? If so, you could ask your endocrinologist to reassess your dose as in recent years there has been research which allows a more gentle approach. They are now able to classify patients by risk and give patients in the lower risks groups smaller doses of levothyroxine and hence avoid hyperthyroid symptoms.

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I cannot figure out why in June the FT4 is below 1! On this link it says a FT4 which is low shows the thyroid gland is struggling. I doubt you had sufficient to convert to T3.

If your GP wont' do a FT3 blood test and if you can afford a private one I'd definitely have it.

I also believe that if you've had a TT the very least they should prescribe is T3/T4. Up-to-date info suggests a therapeutic ratio of 1:3 therapeutic equivalence. If you go to Page 80 on the following link it's on the left-hand side.

This is the link:

Ask your GP for a trial of 3 months of T3 to T4.


No, sorry it wasn't below 1 that would be crazy! In June my ft4 was 20.4! My tsh was 0.31.

I've heard that about the t3 t4 ratio and battles endlessly with private docs as well as GP s over the year who will just not accept it. It's very frustrating! Normally I feel ok, but do wonder if I could feel even better with some t3 in there! Thank you for your response!



One of the Admins had a TT and if you read her profile it might be helpful re thyroid hormones.

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Thank you!


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