Worried low TSH, high T4 and breastfeeding

Hello everyone.

I wonder if you could help me...

I was diagnosed with sub clinical hypothyroidism ten years ago. Blood tests were always borderline and sometimes under normal ranges and as a result I was never prescribed any medication.

September 2015 I became pregnant and my TSH was 3.19. My doctor prescribed 50/75 mcg of Levothyroxine. TSH, FT4 AND FT3 were under normal ranges for the rest of the pregnancy.

I gave birth at the beginning of May. I got tested on 01/07/16 and my TSH was 0.01 and T4 21.2. Doctor reduced Levothyroxine to 50 mcg a day instead of 75 mcg. I got tested again on 07/09/16 TSH was 0.01 and T4 22.2. I understand with these results that I have gone hyper. My doctor has suggested reducing to 25 mcg daily and I havesuggested to her if I could only take 25 mcg three times a week and go without medication for the rest of the week. She said that was ok but she didn't seem too sure. What are your thoughts? Do you think that taking Levothyroxine 25 mcg three times a week is enough? I'm so confused..

Lately I've been feeling really tired but having difficulty falling asleep and also I've been loosing lots of hair. I am really worried as all these months I've been breastfeeding my baby. I understand that Thyroxine only passes into minimal amounts in breastmilk. I'm concerned as I've been taking too much of it, will it then pass into breastmilk?

I'd appreciate your comments. Thanks for reading.

18 Replies

  • It would be really helpful if you could put the range for the FT4.

    But, I will say that the low TSH is totally irrelevant once you are on thyroid hormone replacement. It doesn't matter how low it goes, that does not make you 'hyper' (over-medicated).

    Also, the fact that your FT4 is high, doesn't automatically make you over-medicated. The important number is your FT3 - which, of course, they don't test! Your TSH could be suppressed and your FT4 over-range, but if you're not converting that T4, you're still hypo. It's possible that you need to lower your levo, and introduce some T3, because it sounds as if you're still hypo. But, you would need to get proper tests before doing that.

    I'm sorry, I don't know anything about breast-feeding and over-medicating with T4.

  • Thanks for your quick response.

    Lab range of FT4 is 9.00 - 19.00 pmol/L and the range of TSH is 0.30 - 5.00 mu/L.

    For some reason my doctor didn't check FT3 post pregnancy, it's really annoying. During the pregnany my FT3 was 4.2.

    I really need to get proper testing as you said. I am also going to push for and Endo referral. What tests should I ask for TSH, FT3 and FT4? Anything else?

    I'm just hoping that no thyroxine has passed to my breastmilk and baby. My baby got tested three weeks after birth and she was fine. Will she need any more thyroid tests?


  • I can't advise a lot but I'm a breastfeeding mum and I'm on 100mcg levo. My GP did say ideally weaning would be a good idea but my son is over 3 so it's not as critical as a little one. However, kellymom says no issue as does the breastfeeding network. If you think about it they up your levo during pregnancy and that is no issue, so surely breastfeeding wouldn't be either.

    I've probably confused things even more!

  • Ok, so it's not hugely over range. But you're on such a small dose of levo, l really do think it's not converting very well, and building up in the blood. So, yes you've got to get the FT3 tested.

    So, you need to ask the endo for the tests you mentioned, plus antibodies, if they've never been done. And you need some nutrients tested : vit D, vit B12, folate and ferritin.

  • Thanks.

    I tested negative for antibodies five years ago. Can the result change to positive now?


  • It most certainly can. Either you could have developed it since then. Or, as antibodies fluctuate, you could have just caught them on an off day. Plus, there are two types of antibody : TPO and Tg. Did you have them both done?

  • I understand..

    Haven't had the bloods done yet.


  • My doctor has agreed to have the bloods done again adding all the tests. She said to wait four weeks as to see if there's any change with the meds reduction. I'm tempted to go sooner than that as to find out FT3 level etc.

    What are your thoughts?

  • No point in going back sooner, you would get a false result. In fact, I would leave it six weeks, rather than four, so as to know exactly where I was.

  • Thanks for your help.

    Why do I need testing for those nutrients?


  • People with hypothyroidism are very often low in these nutrients. Added to that you have just had a baby, so you are even more likely to be low in nutrients. I wouldn't worry about your baby getting thyroxine in breast milk. They will have tested the baby in case she was low on thyroid hormones, not high. The nice thing about thyroid hormones is that the Thyroxine we normally take (T4) is a storage hormone. Our bodies convert as much of that as we need at any time into T3, which is the active hormone. If a little bit of T4 is getting through to your baby that will just sit around in her bloodstream and be converted to T3 if she needs it. Her pituitary will notice her T4 levels are a bit higher than she needs and adjust the output of her own thyroid gland downwards slightly to compensate. Her thyroid is working better than yours!

  • Thanks for your reply. It's reassuring.

    I'll be calling my doctor today asking for a new test. I know she's not going to like it as I only had it done last week. I'll ask for : TSH, FT3, FT4, T4 total. Antibodies. Vitamin D. Vitamin B12. Folate and Ferritin. Am I missing anything?

    Thanks a lot.

  • Absolutely no point in doing a T4 total, waste of money. It doesn't give you any useful information. What you need to know is the FT4 because that tells you how much hormone you have that your body can use. The total includes hormone that your body can't use, but doesn't tell you how much of each. So, no point! :)

    Hypos often have low stomach acid - it's the low T3 that impairs the output of stomach acid. So, you cannot digest and absorb as well as you should. BUT you need your nutrients to be optimal so that your body can use the thyroid hormone, whether it's made naturally, or supplemented.

    So, testing those four - the most important four, from a thyroid point of view - it gives you an idea how well you're absorbing. If they are sub-optimal, you need to supplement them to bring them up to optimal. Plus, they all have co-factors, which are also likely to be sub-optimal, so you add them in one at a time. Those four tests give you a base-line to work from.

    Plus, as eeng says, you've just had a baby, and the baby will have been living off your nutrients for nine months, and now you're breast-feeding, so bound to be low. Only difference between you and other nursing mothers, is that you are hypo, and will therefore have difficulty increasing your levels of nutrients to keep both you and the baby healthy. :)

  • Unless you have hyper symptoms your doctor is titrating you meds on TSH alone. TSH is not a thyroid hormone and you should NOT be judged on it.

  • I think i'm experiencing hyper symptoms.. Tiredness and difficulty falling sleep.

    Have you heard about anyone taking Levothyroxine three times a week?


  • I think there's a bit more to being hyper than just that. Those could also be hypo symptoms.

  • No, but then I don't know the vagaries of others. I am not a huge fan of TSH as it seems silly. It is no help once you are taking any form of thyroxine.

  • Hi! Thanks all for your responses. I've just had bloods done again, 5 weeks after previous blood test. I've been on 25 mcg thyroxine. I'll let you know the results as soon as they are available

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