please help! pregnant on NDT and CONFUSED by bl... - Thyroid UK

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please help! pregnant on NDT and CONFUSED by blood results

rosa_rosa profile image

hi all, i hope to get some views on my blood test results as i cant make sense of them.

i am taking NDT wp thyroid brand but i am wondering why my Free T4 is so low ? while tsh is actually supressed. i am 3 months pregnant and i need to get it right for the health of the baby. also what do my antibody results tell you? i got these tests done via bluehorizon privately and just received them.

my results are as follows

tsh 0.03 (0.27-4.20)

total t4 117.8 (64.5 -142.0)

free t4 12.04 (12-22)

free t3 4.58 (3.1-6.8)


anti-thyroglobulin 23.0 (<115)

please help.


15 Replies
SeasideSusie profile image

rosa_rosa I don't know much about being pregnant whilst Hypo but I think I have read that some people go back on Levo for the duration of the pregnancy, maybe it's to do with their being enough T4 for the baby.

Your T4 is low because NDT not only lowers TSH but T4 as well.

Your thread title won't attract the attention of either pregnant members or those who know about it, so if you can edit your title then do so. If it's not possible then make a new thread and ensure the title makes it clear you are pregnant, on NDT and need advice.

Congratulations and good luck with your pregnancy :)

Your antibodies are nice and low and that result does not suggest autoimmune thyroid disease. However, although one positive results confirms it, one negative result doesn't rule it out completely, repeating the test some time in the future would be a good idea.

thank you Susie for your responce. i didnt know that NDT lowers Free T4...

SeasideSusie profile image
SeasideSusieAdministrator in reply to rosa_rosa

Apparently you can edit the title :) . Click on the down arrow V in your first message box and choose Edit. Make the change to your title then click the Edit Response button (I think it's green).

shaws profile image
shawsAdministrator in reply to rosa_rosa

The blood tests we use for testing were introduced for the use of levothyroxine alone. T4 in other words.

NDT contains T4, T3, T2, T1 and calcitonin (last 3 in small amounts).

When T3 is taken or added (or in NDT) to T4 it reduces the T4.

T4 is an inactive hormone and it's job is to convert to T3, so if you take NDT you will have different results than on levothyroxine alone.

This is a link which may be helpful and go to the date July 26, 2007

thank you to all who have replied. shaws does that mean free t4 is not as important? people dont seem to pay as much attention to total t4?

Clutter profile image
Clutter in reply to rosa_rosa


Congratulations on your pregnancy!

Free T4 (FT4) is seen as superior to Total T4 in the UK.

There is scope to increase your current dose to raise FT4 and FT3 but you will probably be pressured to resume Levothyroxine until after your delivery.

Thyroid antibodies are negative for autoimmune thyroid disease (Hashimoto's).

rosa_rosa SeasideSusie

Read the posts by diogenes in the following thread :

I would have said that your results for Free T4 and Free T3 both show under-medication for someone who is pregnant.

free t4 12.04 (12-22)

free t3 4.58 (3.1-6.8)

Free T4 is rock bottom in the range.

Free T3 is 40% of the way through the range.

Free T4 is always lower with NDT when compared with Levo, but still, both your results are very poor, suggesting a raise in NDT is essential.

Bear in mind that for many decades NDT was the only treatment available for hypothyroidism. I'm not aware of any evidence suggesting it caused any damage, but if anyone knows of any I'd love to see the links.

rosa_rosa profile image
rosa_rosa in reply to humanbean

thank you Humanbean for your thoughtful reply... the only thing increasing the dose would make my tsh even more supressed?

humanbean profile image
humanbean in reply to rosa_rosa

Suppressed TSH would worry a doctor, but patients with hypothyroidism usually learn that TSH has no effect on how people feel, nor does it tell you anything about how well or ill the patient feels. TSH is a pituitary hormone, not a thyroid hormone.

If you want to know what your thyroid hormones are actually doing the TSH is not reliable, you have to have the Free T4 and Free T3. Sadly, doctors think the TSH is set by God and has more importance than measuring the actual levels of thyroid hormones.

yes,its very frustrating. all the gps ive been to dont seem to have a clue. the gp i spoke to today said my results are great , dont do anything! thank you humanbean....

I have had 2 healthy pregnancies on NDT.

Some docs say you should take T3 whilst pregnant as it can cross the placenta. Some completely disagree. Most don't know. I wouldn't give mine up, but I am not a doctor.

Check out @ buy her book advertised on her website.

As soon as you are pregnant increase your dose & you willowy likely need to increase through your your pregnancy. (The book gives you advice on how much & when)

thanks Eleanor. glad you were fine with your pregnancies.

Congratulations on your pregnancy!

I am currently on my 3rd pregnancy with an underactive thyroid. I take NDT.

Go to the website, It has lots of great articles, (I have included some thyroid/pregnancy articles at the bottom) and advice you can take to your GP. (You GP will know very little about the thyroid in pregnancy, so it is very important for you to get as knowledgeable as you can. If you are lucky, you will have one like mine, who is very open minded and willing to read the articles and go with my suggestions.) Buy the book she wrote on pregnancy-it’s amazing! “Your Healthy Pregnancy with Thyroid Disease”, by Dana Trentini & Mary Shoman.

Once you find you are pregnant, then increase your Levo/thyroxinne (T4) by 30% immediately. The demand increases as soon as 4-6 wks into pregnancy and we are trying to avoid miss carriage. Then go to your GP and let them know you need blood tests every 4weeks until 20weeks. The results of these tests, will likely show that you need further increases. (Don’t increase without the blood tests to tell you how much you need.) Your blood tests need to include T3 results. If your GP won’t do this, get private testing done through “Blue Horizon.” As always, get copies of all your blood tests, and post on here for advice. Do not accept your GP telling you that you are “normal” or “within range” as very few of them know what is healthy for pregnancy. At 20 wks, the demands usually plateau and you will need tests/increases less often. (The book tells you how often.)

If like me, you take NDT (T4 and T3) rather than Levo/thyroxine (T4) then the instructions for increasing are not as straight forward, but can and must be done. To get advice, I emailed Lyn Mynott who began Thyroiduk: I put “Pregnancy Guidelines” in the subject line and she asked a doctor for me. He advised that I follow the instructions for increasing levo, but that I shouldn’t increase T3 at the same rate as increasing T4. (This was easy for me, because I take NDT plus extra T3.) You will read some articles saying that you shouldn’t take T3 in pregnancy as it crosses the placenta. I and this doctor, consider this to be untrue, but you need to do your own research.

The book I mentioned above, gives this advice about the TSH levels you need to have to have a healthy pregnancy. This is really helpful to take to your doctor.

"First trimester: less than 2.5 with a range of 0.1-2.5

Second trimester: 0.2-3.0

Third trimester: 0.3-3.0.

TSH should be monitored every 4 weeks during the first 20 weeks of gestation, then once again between 26 and 32 weeks"

If you are on NDT (Ie. Taking T3, your TSH should will be almost 0 with a low T4 in pregnancy (and non pregnancy)

Keep an eye on your B12 levels, as pregnancy places a high demand on these and people with an underactive thyroid are usually deficient to begin with.

Some articles, you may like to read:

wow Eleanor, so much useful information...thank you for taking the time to write this. i have copied it all to review again, in case it gets deleted from here. i might come back to you with any questions, if thats ok. i havent been monitored. gp doesnt seem to care. i had a private test with blue horizon this week, its good but expensive... gp wont test t3. thank you darling again! and wishing you a healthy happy pregnancy . how many weeks are you?

hi Eleanor, i ve read the links but couldnt find on hypothyroid mom s website any suggestions on what free t4 should be on ndt. based on your previous pregnancies what would you say free t4 should be and how much i should increase my dose by? i was on 1 grain and a quarter , and from today increased it to 1 grain and a half. i know you said that free t4 should be lower on ndt than on levo , but how low is ok? i am trying to get a hold of an endocrinologist but in the meantime would really appreciate some guidance.

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