T3 and TTC?

[Needlehaystax]

Hi there I’ve just been told by my endo that I can’t start T3 meds if trying to conceive - is this the last word or is it debatable? Anyone tried to conceive on T3 on here?

[jimh111]

Around 99% of babies are conceived on combination therapy, from their mother's thyroid. Nasty dishonesty from endocrinologists.

[Needlehaystax in reply to jimh111]

could you expand? So you are saying that people are ok TTC and T3 meds? If anyone else has any answers let me know

[jimh111 in reply to Needlehaystax]

This kicked off a long time ago when one or two studies showed T3 did not readily cross the placenta because of high D3 activity. (D3 is type-3 deiodinase, an enzyme that converts T4 to rT3 and T3 to T2). However, these experiments were carried out in afterbirths (the baby hangs onto the placenta before birth). Thus, they show what happens in the later stages of pregnancy when the baby has a functioning thyroid and is independent of the mother's thyroid hormone. I believe the baby does not have a fully functioning placenta until around four months, around the time it switches to its own thyroid. So, the 'evidence' supplied by endocrinologists is suspect, but it makes sense to be cautious.

The 'T3 doesn't cross the placenta' theory doesn't stand up in practice. First there was a doctor in the USA (John Lowe) who prescribed high doses of T3 for fibromyalgia, many of his patients had successful pregnancies.

Stronger evidence comes from the fact that NDT, which has a high proportion of T3, has been used for over a century and is still widely used in the USA. I know of no reports of it causing problems during pregnancy.

And of course our thyroid supplies T3 (around 6 mcg daily). Thus, the vast majority of humans and all animals are conceived whilst on combination therapy.

It may be that high doses of T3, or indeed levothyroxine monotherapy, leads to a slightly higher incidence of birth problems, we don't know because it has never been tested.

It would seem that combination therapy that mimics normal hormone levels using up to about 10 mcg T3 would be perfectly safe. I would use caution with high doses of T3 because reports of its safety are anecdotal, there are no studies. As far as I know there has never been a study into the safety of levothyroxine monotherapy during pregnancy. There are anecdotal reports of women achieving pregnancy when adding some T3 to their levothyroxne.

[Needlehaystax in reply to jimh111]

thanks so much for the helpful info

[radd in reply to Needlehaystax]

Needlehaystax

Great comprehensive response from jim. I would add many female hypos might require a little T3 meds added to their T4 in order to conceive and retain a healthy pregnancy. It depends upon TSH and T4 levels, both of which become crucial during pregnancy.

[serenfach]

Ask him for proof! Gaslighting twunt!

[humanbean]

This link is about a woman who took T3 only throughout two pregnancies and her children were perfectly normal and healthy.

endocrine-abstracts.org/ea/...

Click on "Download e-Poster" to see the poster at a readable size.