Thyroid UK
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Low tsh and miscarriage/pregnancy? Also t3 during pregnancy?

I am looking for anyone whos had a healthy pregnancy with a low tsh.

I was diagnosed hypo about 5 years ago. I had such bad fatigue at the time I was mostly bed bound.

My results back then were free t4 7, tsh 11. Im not sure what my t3 was.

I was put on 100mcg levothyroxine and did feel an improvement but still suffered with bad fatigue and was.diagnosed with m.e

Then about a year ago I saw a different endo who suggested trying t3 as well. It helped enormously but I was very sensitive to it and we eventually settled on a dose of 75mcg t4 once a day and 2.5mcg t3 three times a day. I felt the best I had foryears. Not perfect but much better.

We started trying to concieve and fell right away. At 6 weeks the scan showed a healthy heartbeat.

Also at 6 weeks my endo stopped my t3 and increased my t4. My bloods were normal but he said t3 was too unstable to manage in pregnancy so its better just to have t4. I was not happy as I knowthe t3 would leave my system within daya but the t4 would take weeks to have effect so basically he was reducing my dose, til the t4 kicked in.

A few weeks later I miscarried and the scan showed the baby stopped growing around 7 weeks.

Could be unrelated. Anyway my lovely endo referred me to his professor saying he had more experience in pregnancy.

I went back on my original dose but when I saw the prof was told my tsh was way too low 0.02 so I had to reduce my dose, even though my free t4 was only 12 and t3 was 5.5. I was very cross as I know takimg t3 can supress tsh but did as I was.told. Reduced to 75t4 daily and 2.5 t3 twice daily.

I went on to have another miscarriage a few months later.

I was told my tsh was still way too low (still 0.02!) and it was possibly not helping the pregnancies. I asked if there was any link between low tsh and miscarriage and the prof said no but it was the only thing he could think of!

I tried cuttimg out the t3 but was so ill that its not an option.

So I am now on 50mcg t4 a day and 2.5 t3 twice a day and feel it isnot enough. I am having bloods done in dec (after beimg on this dose for three months) and not trying to.concieve til my dose is stable. Also having other miscarriage tests.

But really want to know if anyone has had a healthy pregnancy with a low tsh? As iI dont think it is the cause of my problems.

Thanks so much in.advance, any info on thyroid and pregnancy welcome!

20 Replies

Just to rule it out and a long shot here, please make sure your GP or consultant obstetrician or Endo or whoever you trust does the tests for Hughes Syndrome on you. I am sure it probably is just a thyroid problem. However people who have Hughes Syndrome often have many miscarriages and usually have a thyroid problem also. The blood tests are simple and cheap to do. It would be wise just to make sure by ruling it out, as it can be undetected due to medical teams having not heard of it, but more common than you may think


I see Professor Hughes himself regarding my Systemic Lupus and Hughes Syndrome and he is always on the ball and looking out for hidden thyroid problems.

Mary F x


Hi Mary, thank you so much for your reply :-)

I have been tested for hughes, thankfully I have a great gyne who is testing for every possible thing!

Im also see a private gyne to have my natural killer cells checked. So many possibilities.

Thank you again x


I am pleased to hear this! Make sure they check your progesterone levels also... but I am guessing by what you say that you have good care! Best of luck to you. Mary F x


I'm so sorry to hear your story. Those miscarriages must have been heartbreaking.

You might also want to investigate this line of thought:

Sometimes the use of prednisolone (slow release hydrocortisone) in pregnancy is important. My daughter in law had several miscarriages then saw Dr. Quenby privately (one of the Drs involved in the study above). My son and daughter in law now have 2 beautiful daughters.

Jane x


Thank you so much for your thoughtful reply, im so sorry to hear about your daughter in law. I am see prof quenby a week today for the unk biopsy and will try steroids next time whatever the unk results. So glad to hear your son and d.i.l's success!


Miscarriages are common in hypothyroidism especially when undermedicated so it could be that get you gynae to check for antiphospholipid which causes miscarriages in very early pregnancy my friend has this and lost 8 because of it


Oh gosh your poor friend. Yes I got the all clear for that test but thank you xx


If you lose more and i dont wish that on anyone by the way insist the doctor restest you for it my friends first one came back negative and after she lost more the doc decided to retest and it came back positive so one negative doesn't necessarily mean you don't have it. She went through such a hard time and i wouldn't want anyone to suffer like she has it nearly broke her


wow that's scary that it can be negative then positive! I am having it done a second time next month but will keep that in mind and will ask about taking low dose aspirin during the pregnancy also just incase.


I don't have an answer for your situation, but just wanted to say I have known a few women with a suppressed TSH and on T3 and/or NDT having a successful pregnancy, sorry I have no studies/research to support this, just 'personal life experience'

best wishes x

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Thank you it is reassuring to hear that xx

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Just a different angle to explore, have you had your B12 and folate tested? Sometimes taking folic acid when trying for a baby can mask a B12 deficiency. Both B12 and folate are vital for a healthy pregnancy, but for reasons completely unclear to me we are only advised to supplement folic acid. Some more information here:

And some info about testing for B12 deficiency/pernicious anaemia:

GP's can do the basics - serum B12, folate, ferritin, anti-intrinsic factor, anti-parietal cells. But the more accurate tests are active B12, MMA and homocysteine.

I wish you well and hope you find some answers.



very interesting, thank you Hampster. I am down to have my b12 and folate checked on my blood test next month so will be interesting to see what they are. thank you xx


I had 8 miscarriages and my endo said that my TSH for pregnancy had to be maintained at 1.0, he said it shouldn't go above 1.5 and not below 1.0 - to do this my levo dose went up through pregnancy from 75mcg to 125mcg daily, I've never been on T3, I was having 2-3 weekly blood tests to keep track of it - sounds a lot but was well worth it as I had a healthy baby boy at full term a year ago - hang in there, I was also referred to Professor Regan at St Mary's Hospital, London


Oh hun I'm so sorry, you are one strong lady and I'm so glad you got your little boy in the end! Can I ask what your levels were during the miscarriages? thanks for the info xxx


Hi, so sorry to take ages to reply, have been a bit under the weather, the levels I had when I miscarried were between the TSH 0.02 - and below 1.0, had a couple that were above the 1.5 TSH, the consultant advice was to keep between 1.0 and 1.5 and this seemed to work, I hope that helps, all the very best of luck to you, Sarah xx


Sorry, didn't finish my last message properly, just to say good luck and best wishes,

Sarah x


Hi. I currently have the same situation as yours 2 yrs ago. I miscarried twice in the last four months but my first pregnancy was fine, and she's now 3 yrs old. I can't think of anything else (aside from my age, I am 34yo) but my thyroid not being stable. I was diagnosed of hyperthyroidism 10 yrs ago then I had my radioactive done which I became hypo. It was fine and stable during my first preg. Second preg tsh was a little bit high from the normal range, about 4.9 then 3rd one was a way too Low like yours 0.02.

It's been 2yrs, can you please let me know what was the findings? I hope they were able to figure it out and hoping you have your baby now.

Looking forward for your response. Thank you.



Hi there

It turned out I had high nk (natural killer) cells which is more common in people with autoimmune diseases such as thyroid issues.

My gp referred me to dr shehatas gynecological clinic in Epsom through choose and book as I am in portsmouth.

Dr shehata is one of two doctors in the uk with experience treating this, the other is sioban quimby but she is private only.

It turns out I needed prednisone steroids from ovulation along with high vit d, mumomega fish oils, low dose 75mg aspirin, progesterone suppositories all til 16 weeks and clexane injections til 39 weeks. Not everyone needs the injections though.

my thyroid needed careful monitoring throughout and after birth

I hope that helps. Good luck xxxx


I know this is an old post so not sure if you'll see this but I'm interested to know if you continued with a T3/T4 combo and low TSH through your successful pregnancy? Or did they switch you to T4 only? Thanks and congratulations on your baby x


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