Hi everyone my daughter is 20 weeks pregnant and has received a letter yesterday from an endo at the hospital she is under telling her to immediately stop Liothyronine and increase 25mcg levothyroxine. She has the Dio2 genetic mutations and was not doing well on levothyroxine alone and has been doing well by adding Liothyronine last year . I am very concerned they have asked her to stop 20 weeks in to the pregnancy and think I have read the risk of miscarriages ?
Please can anyone share some information to support taking liothyronine during pregnancy
Many thanks
Fae1960
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Fae1960
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I don't know whether stopping T3 part way through pregnancy would cause a miscarriage, but switching treatment so dramatically midway through a pregnancy is probably not a good idea.
I know it is only a single case report, but you and your daughter may be able to make use of this :
I would absolutely second human bean, I do not think that stopping T3 during pregnancy would be a wise idea at all. Did they even use blood work to make this decision?
We don’t think so just nhs policy to only treat with levothyroxine during pregnancy ! My daughter was waiting for a referral to endocrinology from GP surgery but it hasn’t happened and was asked to contact the endocrinology dept who prescribed Liothyronine They requested bloods but GP only did tsh, ft4 even though they know she is on t3 and they sent a letter to my daughter saying stop t3 immediately and increase levo by 25 mcg they would not have received these blood tests when the letter was generated !
for goodness sake! I am so sorry you are dealing with this. How can they dish out this kind of advice without even testing her FT3 when she is actually being treated with T3 on NHS?! Their incompetence is scary sometimes. I don’t know anything about your daughter’s bloods or situation, but if it were me I wouldn’t think ADDING some T4 for the pregnancy would be the end of the world if she can tolerate it, but taking away anything at this stage seems bonkers, especially based on zero data as Helvella says x
They will say that they have no (or limited) evidence for taking liothyronine in pregnancy, and that is why she should stop doing so.
Maybe you should ask what evidence they have for the advisability and safety of stopping liothyronine while pregnant?
I can’t see what dose of liothyronine she is on, but adding 25 micrograms of levothyroxine appears to come from the advice to increase levothyroxine by 25 micrograms when pregnancy is suspected. And not from careful study and understanding of her current regime.
That advice is just meant to be a first aid level to ensure that thyroid hormone levels don't dip due to the pregnancy.
hi thank you for the reply so she was on 100mcg levothyroxine and 10 mcg Liothyronine and when she realised she was pregnant bloods where taken by GP and no advice was given on dose increase and she was referred to midwife for care at 12 weeks - so reading up on pregnancy and how important t4 is she upped her dose to 125mcg levothyroxine and stayed on 10 mcg Liothyronine midwife said she would need to see a consultant probably diabetes clinic but no appointment has arrived. She spoke to gp to get more levothyroxine as she had increased dose and was running low and gp couldn’t generate endo appointment and asked her to contact endocrinology who prescribed t3 she has a telephone appointment tomorrow, she is now 20 weeks and due a scan on Wednesday . So online I found information to say Pfizer and Teva say it is ok to carry on taking t3 during pregnancy My daughter is on Roma they say ask pharmacist or on Gp advice .
they don’t have the blood results and certainly not ft3 even though daughter reminded gp she on t3 a complete waste of time ! You have given us some great questions for them to answer ! And daughter won’t be adjusting t3 dose unless they know better than the vast number of years research the pharmaceutical company’s have probably had to do to get this medication accepted for use ! Daughter also told probably no atenatal classes on nhs as oversubscribed shocking
I think that's terrible advice. There are many women who successfully deliver babies on T3 only! These doctors are terrified of T3. They seem to have no understanding of it at all. No way should anyone stop her T3 without even testing it!
This might be a battle, but it's one she needs to fight hard for. She needs that T3 for a reason. She's done a Levo increase, now she needs monitoring on that dose.
There's a lot of info about thyroid treatment and pregnancy on the ThyroidUK web site, so she needs to comb through that. Depending on how she felt before T3 was added, she is going to need to stand her ground.
my daughter was struggling for years - months off of work last year and attended ME clinic frightened she would lose her job and home and with advice from this wonderful site we decided to do a genetic test and she tested positive 2 Dio 2 genetic mutations which she then pushed for a trial of t3 and her life has completely changed for the better - she couldn’t have thought about having a baby before t3 she didn’t have the energy to look after herself . She does just need monitoring!
If her doctor won't give her the prescription she needs, suggest she arranges a phone appointment with the prescribing pharmacist at Roseway Labs with a view to buying her T3 from the lab with a prescription provided by the specialist.
So far I have found that prescribing pharmacist to be so much more understanding than any GP or endo I've seen on the NHS. She's great. She might have a view on the pregnancy. But if she has any sense at all that view should be that the T3 is vital to continue so as not to starve the growing baby of it. At this stage the baby is reliant on the mother's thyroid hormone.
It's £30 for a consult. She will need to send in her most recent blood results too. Which can be got from the surgery. I have been so relieved to find that service available to us in the UK. It's relatively new though, so I hope they continue it.
Reasons why doctors tell women to stop taking T3 during pregnancy :
1) The first and most obvious reason is because they have been brainwashed in to believing that T3 is dangerous - despite the fact that if you gave a doctor a blood test they would have measurable levels of T3 flowing through their veins and could well have more than the pregnant and hypothyroid patient sitting in front of them.
If you are worried about the supposed "dangers" of T3 then please read this link :
2) Doctors have been told that T3 doesn't cross the blood-brain barrier so the embryo/fetus/baby won't have any thyroid hormones and won't grow, or won't grow properly if they don't have enough T4 from the mother. This is complete nonsense in my untrained opinion. Every patient who needs T3 and gets it, find that it affects their brain - they can think again!
3) This next one is just a guess so take it with a pinch of salt - I don't have proof of what I'm saying but it makes sense to me. I have no medical training.
When a woman is pregnant she gets given blood tests of many kinds. But doctors can't give an embryo or fetus a blood test during pregnancy unless the circumstances are very, very unusual indeed. So doctors have decided (for some unknown reason and without evidence that I can find) that babies only use T4 from the mother, not T3 (which, in the fully formed human, is the active thyroid hormone required by every cell in the body). I wondered where doctors got this idea from. They seem to be suggesting that the placenta carefully filters the mother's blood to allow some T4 through the placenta but actively blocks T3 and prevents it from reaching the fetus. So a hypothyroid patient taking T3 only would have very low levels, possibly even zero amounts of T4 for the fetus. I can't see why the placenta would do that - but I'm not a doctor.
The US has a different attitude to T3 in pregnancy :
I think that researchers might use the afterbirth as research material when wanting information about blood levels of various substances in the newborn's blood. (Very few parents would allow researchers to start using their babies as test subjects immediately after birth.)
In the very early stages of pregnancy the embryo/fetus has no thyroid of its own. It is totally reliant on the mother's thyroid hormones. But the thyroid starts to develop very early. I found this link about embryology and thyroid development. I warn you it is mostly hard going, but the Introduction mentions some of the things I wanted to point out.
The thyroid is one of the earliest endocrine organs to differentiate and has an important hormonal role in embryonic development. The early bundle of cells then forms the thyroid by first dividing to form 2 lobes separated by a narrow connecting isthmus.
In the first trimester, the developing fetus is initially dependent upon maternal thyroid hormone crossing the placental barrier.[1] Around week 16 (GA week 18) the fetal thyroid becomes active enough to support the fetal requirements for neural development.
Maternal thyroid hormone - required for early stages of brain development (Maternal Thyroid recent studies show both high and low thyroid hormone impact)
Fetal functions from week 10 - required for neural development, stimulates metabolism (protein, carbohydrate, lipid), reduced/absence = cretinism (see abnormalities)
So, the fetal thyroid is fully functional by 20 weeks of pregnancy and no longer relies on it's mother's thyroid hormones to make T4 and T3 because the fetus is making its own.
If you look at the diagram under the title "Thyroid System and Neural Development" on that link I gave, you can click on the diagram and make it bigger.
There is lots more to the creation of a fully functioning thyroid than that. Although the fetus is making its own thyroid hormones halfway through pregnancy it doesn't have all the bits it needs to control its own thyroid hormone output - it has a pituitary by week 12 but doesn't have aa fully functional hypothalamus until week 35.
Anyway, if researchers are using the afterbirth to look for T3 they probably won't find it because the baby is making its own thyroid hormones by then and has been for half the pregnancy, and doesn't need thyroid hormones from the mother.
If the mother was still supplying thyroid hormones to babies throughout the second half of the pregnancy the baby would be born hyperthyroid.
I hope this makes sense to someone. Apologies if it doesn't.
Thank you for all your replies yesterday sending information and research articles !
Daughter’s telephone appointment went well this morning her levothyroxine was increased and she has held on to her t3 - consultant tried to take it away but my daughter said with the delay in getting to see anyone the damage if any ? has already been done now at 20 weeks pregnant ! The benefit to her is worth the risk now so she has decided to carry on taking it and takes full responsibility for her decision, which she has had to put in writing !
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Introduced t4 back in to regime with my liothyronine should I increase dose. 
Does Liquid Levothyroxine contain a specification limit of Liothyronine?
LIOTHYRONINE 
It's a worry when you have to explain the difference between Liothyronine and Levothyroxine to your Pharmacist
T3 replaced by Liothyronine sodium
