Decreasing T4 Whilst Pregnant

[WesleyM19]

Hi All, this is my first time posting so I appreciate any advice you can offer.

I am 18w2d pregnant, and have been advised to drop my T4 dosage from 137.5mcg to 100mcg by my obstetrician. I currently take 19.25mcg T3 daily (3/4 of a 25mcg tablet) and an iron supplement as well as normal pregnancy vitamins - my most recent blood test results can be seen in the photo. I have taken T3 for around 4 years and started on T4 in August.

Obstetricians rationale is that because my TSH is suppressed, this is likely to mean I am over medicated on T4. I explained that I am taking T3 which causes suppression, and I am experiencing symptoms of undermedication (extreme tiredness, brain fog, aches and pains - I realise these can be tricky to separate from pregnancy symptoms). My T4 levels have decreased steadily over my last 3 blood tests (7th November - 16.7, 12th December 15.1, 31st December 13.0). During this time my T4 dosage increased from 100mcg to 137.5mcg. She has asked me to reduce T4 for 4 weeks, have a repeat blood test on 8th Feb and then I will have an appointment with a specialist pregnancy endocrinologist on 15th Feb.

I'm not keen to lower my T4 dosage when it is falling steadily on its own, despite increases in dosage. I'm aware there can be some serious complications if my T4 falls too low - I'm unsure whether to follow the advice of the obstetrician or wait until I see the endocrinologist.

Is there a chance I am overmedicated on T4? Is it worth dropping dosage now or waiting until I see the endocrinologist?

Thank you!

[SlowDragon Administrator]

If anything you need dose increase in levothyroxine....Ft4 is near bottom of range

It’s extremely important to maintain good Ft4 during pregnancy.....there’s some debate wether only T4 crosses placenta

Hopefully someone whose had successful pregnancy on Levothyroxine plus T3 will pop along

Is your T3 self medicated or are you under an endocrinologist care

Suggest you refuse to reduce levothyroxine.....possibly consider increasing it

[WesleyM19 in reply to SlowDragon]

Thank you for your reply.

Increasing was my gut reaction too when I saw the blood results, and went into the appointment asking for this to happen.

My T3 is self medicated, I monitor regularly with private blood tests have just decreased my dose as I was slightly above range previously.

I am speaking to the department again tomorrow to get some evidence for working from home, so I will mention that having thought about it, I don't feel comfortable reducing my dosage and I will push for an increase at my appointment with the endo.

Thanks again!

[SlowDragon Administrator in reply to WesleyM19]

T3 shuts our thyroid right down, so it’s essential you and baby have enough thyroid hormones

Most medics are just TSH obsessed

It would take months for a suppressed TSH to climb.....if ever...and unlikely with Hashimoto’s that you have any ability to make any thyroid hormones yourself

They can’t seem to think outside the box

[WesleyM19 in reply to SlowDragon]

I agree - when I mentioned TSH level being low because of T3, she brushed it off completely!

It's such a shame that so many people have to fight so hard to be treated properly!

[tattybogle]

seems to me that fT4 is low enough anyway , i wouldn't want to reduce that further , especially while in the middle of a pregnancy. Since you're taking some t3 , it is presumably mostly the T3 that is the cause of your TSH being low, and i doubt that a reduction of Levo would have much effect on raising TSH,

I think , unless you feel confident that the obstetrician is experienced with both pregnancy thyroid levels AND medicating using T3, i would be as unsure as you about following the advice to reduce Levo. especially since both your fT4 and fT3 seem to be well within range.

Is the endocrinologist likely to be any better ? was it them who prescribed t3. Could you get a phone consult with endo before you do anything ?

[tattybogle in reply to tattybogle]

p.s i also think that 137.5 to 100 is quite a significant drop in Levo dose, they could have suggested taking 125 or 112.5. I really notice a reduction of only 12.5 mcg in Levo in how i feel , even if it doesn't have a big effect on results.

( But i still don't see the logic in reducing it at all with your current fT4 level)

[WesleyM19 in reply to tattybogle]

Thanks for taking the time to respond.

I'm not sure if the endo is likely to be any better, but the obstetrician said she has never prescribed and managed T3 throughout pregnancy, so I think can say fairly certainly that she is NOT experienced.

My T3 is self-medication - I monitor levels with regular private tests and have recently reduced as I was above range slightly.

I think I'm going to let them know I won't be decreasing my dosage, and wait to see the endo in 4 weeks time. Hopefully they will have managed a T3/T4 pregnancy before!

Thanks again, it's really helpful to have some objective input.

[tattybogle in reply to WesleyM19]

As far as i know When just on Levo , it is usual to increase dose slightly for the first trimester , to aim for a lower TSH , which is in line with what the body naturally does to accomodate the need for extra hormone capacity in pregnancy .

I have a very detailed paper on hypothyroidism in pregnancy, which is probably far too detailed for comfort, but i'll link to it in case you can find anything useful in it, and cross my fingers and hope you don't find anything too scary in it.

If memory serves correctly , somewhere in it are the proper TSH ranges for each stage of pregnancy, and how the T4 and T3 hormones are important at different stages.

ncbi.nlm.nih.gov/pmc/articl...

[WesleyM19 in reply to tattybogle]

Wow... I’ll definitely be taking that with me to my next appointment! Very interesting and quite clear (to me at least) that reducing dosage is the last thing I should probably be doing! Thanks, interesting read.

[humanbean]

Some links on the subject of taking T3 or NDT during pregnancy that you might find helpful :

healthunlocked.com/thyroidu...

healthunlocked.com/thyroidu...

healthunlocked.com/thyroidu...

healthunlocked.com/thyroidu...

endocrine-abstracts.org/ea/...

In the last link, click on View ePoster or Download ePoster to be able to read it properly.

[WesleyM19]

Thank you, I’ll have a read this evening 😊