Thyroid UK
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Thyroid levels and Breastfeeding

Hi Can anyone advise please..My latest Thyroid results are

TSH 0.05

T4 23.3

T3 5.0

and I am on 175mcg Thyroxine daily. I have recently had a baby (6 weeks ago) and am breastfeeding also have PA. My bloods were taken 7 days ago, I called my GP surgery today and was advised that the GP flagged up the results but no callback available until next week!

I was thinking I should reduce my dose to 150mcg daily...any advice would be very helpful.


13 Replies

Without the lab ranges I can't be sure, but yes, you could cut down to 150mcg a day. Did you increase your dose of Levothyroxine when you were pregnant? Have you returned to your pre-pregnant dose yet?


Thank you,I had already reduced my dose to 150mcg. My usual dose is 125mcg daily, I've asked the GP to repeat bloods monthly whilst breastfeeding so we can monitor when meds need to be reduced again.


It's possible to freeT4 range is 10-22, or even lower than that, which would put that a tiny bit lower.

However, with a freeT3 of 5 I think it's unlikely to be over range. The top of the range is often 6.8, although it can be lower.

Unless your freeT3 is over range, you aren't over medicated, and its common to need an over range freeT4 to get freeT3 high in range.

How do you feel on this dose? Any problems? Better or worse than on your pre-pregnancu dose?

Because I think your doctor is likely to recommend a decrease. They will probably look at the TSH only, which probably is below range. Although many people need a suppressed TSH to feel well, and yours is not especially low.

So it really depends on your own symptoms whether you want to fight it. Your current dose is a completely fine one to stay on if you feel better with it. If you don't feel any improvement from lower doses you've tried, or if you feel less good on this dose, then you might as well go with whatever the doctor suggests. Symptoms are the most important thing. My guess would be that you'd feel better with this dose that 25mcg less, but everyone is different.


Thank you, I have since reduced my does to 150mcg, its hard to tell exactly how I feel as sleep deprivation is now also added to the equation. My usual dosage pre pregnancy was 125mcg and thats where I felt the most comfortable.


SB75, good that you're happy on that dose. Do be careful and keep an eye on the changes when you reduce your dose. If this blood test is representative (and it may not be depending on how long after the birth it was and how long you'd been on that dose) your freeT3 looks like it's currently as low as you want it to be (although again there's the caveat that I havent seen the rangers. You may have an unusual lab. I'm assuming the top of the range is about 6.8).

Make sure you're really clear which dose you feel better on, and don't be swayed by pressure from doctors, who will generally push the dose as low as they can get away with. This can leave patients very ill, or just a bit less well than they would be with the dose a tiny bit higher.


Thank you for your advice ;)

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Hi SB75,

Firstly, many congratulations on your baby, what did you have? :)

Your bloods T4 and T3 are slightly elevated. Did the GP increase them when you were pregnant? If so, I would call the GP again and ask for an emergency call back and tell them you are breastfeeding. The baby will be getting some of the medication as well.

But saying that, I would not reduce medication until you have spoken to your GP first though.

Take care and don't take "no" for an answer from the receptionist. After all they are not medically trained, as they like to tell us when it suits! ;)

Let us know how you get on.

:) xx


Thank you, I had a baby girl, she 7 weeks old. I had already reduced my dose to 150mcg because my Endo after my last pregnancy reduced my dose gradually down to 125 which is my regular dose.

After reading your message I phoned the receptionist and she said no call backs were available, I told her I am breastfeeding so she then said I could email and get a response within 48 hours so I emailed the GP and said I wanted a response asap and thankfully he emailed back the same day and advised that I should reduce to 150mcg daily.

They want to repeat bloods every 3 months but whilst I am breastfeeding I am requesting them monthly and I will not take no for an answer.

With my son (who's 3 now), I was only able to BF until he was 4 months, my milk supply ran out and by the time I had TSH levels etc tested it was too late to investigate why this may have happened.

Thanks again for your encouragement, I really appreciate it.



Oh Wow to your little girl, again congratulations.

I am glad that the GP emailed you back and at least it gives you a little peace. But you are right, bombard them if you have to as your health is important and obviously you need to be super fit (or try to be) with two little ones.

Ironically my milk rang out after a few days with my second one, she was such a hungry baby and I don't think I was making enough to sustain her. I fed my eldest for eight months. I was sad about it, but sometimes it happens.

Keep us posted and hope you get on ok. But please message me anytime you want, happy to help.

Take care

:) xx


Thank you! I spoke to the GP yesterday and they wanted to repeat bloods after 3 months, in the end we agreed on 6 weekly! How old are you children?

That's great to hear that you were able to feed your first for 8 months, well done ;) Can I ask, do you know why you ran out of milk with your 2nd? I had read somewhere that many Hypo women have had difficulty sustaining breastfeeding...


Oh great that you stuck to your guns, you go girl! My babies are most probably your age lol. My eldest is 32 and my youngest will be 30 this summer.

With my first baby, I had loads of milk, too much lol but my first baby would only take from the nipple and not the bottle even if I got nibble shaped teats lol. I stopped at eight months because she was teething and was constantly needing comfort and mummy was getting very sore. So it took a while and trying to disguise the teats etc but she went onto a bottle for a while and her last feed of the day, was breast fed until she decided that she did not want it anymore.

With my second, unfortunately my eldest got a virus and was on antibiotics, so my baby had to have some too to avoid getting the virus and subsequently bless her, got thrush and gave it to me :( She was also a very hungry baby and all sorts of problems started, so I decided with a heavy heart to put her onto formula, it took a while because she had reflux problems, so she would throw up the first feed but keep the second one down??

Had I not had the above problems, I think I would have had the same amount of time with her. I was unable to have anymore children after that because the powers that be, started messing my medication around. As a result I have had five miscarriages, the last one being a set of twins and very heavy periods. But I feel blessed I was able to have had my girls.

I am glad that you were able to stand your ground with the surgery, as should be your right. At the end of the day, your body, your choice and decision especially with a young family.

:) xx


I'm so sorry to hear about your awful journey of miscarriages, I can't begin to imagine, I hope your meds are now stable. Are you on Thyroxine? Its often harder breastfeeding with the second, I am hoping that this time I will be able to choose when to stop rather than nature/hormones deciding!


1 like

Thank you SB75, It just wasn't meant to be but at least I am a very proud mother of two beautiful girls. :)

Yes I am on thyroxine and lithyronine.

I hope all goes well with the breastfeeding and take care. Always here for a chat.

Take care :) xx


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