I’m 22 weeks pregnant. I was hyperthyroid at the start of my pregnancy but I’ve had medication to bring my numbers down. I was wondering why my TSH is still suppressed? Is there a reason for this. Also does it matter if it’s suppressed but my free T3 and T4 are fine.
I’ve reduced my dosage myself as my endo is focusing on my TSH and not on the fact that my FT3 and FT4 have come right down again. I want to stop the medication completely but not sure if this is ok if my TSH is still suppressed? Also could I slip into hyper again? She’s reduced me to 5mg of carbimazole but I’ve started taking 2.5mg as I don’t want my T3 and T4 any lower as then I’ll risk being really hypo.
When I was first diagnosed hyper my results were
FT3 11 pmol/L (3.1-6.7)
FT4 36.1 pmol/L (10.8-25.5)
However after about 13 weeks on carbimazole and gradually reducing my numbers are now
FT3 4.3 pmol/L (3.1-6.7)
FT4 11.3 pmol/L. (10.8-25.5)
Should I just stop the carbimazole completely as my numbers are so low now? The only reason my endo still has me on it as she said my TSH is still suppressed !
Would love any advice
Thank You!
Written by
Ayesha83
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My TSH hasn’t risen into range in the 2 years since I was diagnosed and medicated with carbimazole.
The TSH can take a while to respond and in some it takes longer to recover or permanently remain discordant to the levels.
I was mildly hyper from a solitary hyper nodule at least 4 years before being diagnosed (wasn’t told). So I have had a suppressed TSH for a long time. It only raised a fraction when I have low thyroid level for months. Maybe my TSH has given up after so many years. I think it’s referred to as HPT axis downregulation. (hypothalamus–pituitary–thyroid).
I thought pregnant patients must be switched to PTU? Which is safer in pregnancy? Was this not done in your case?
Perhaps discuss with your doctor regarding your levels being ignored in favour of the unreliable TSH. If you self tweak make sure you have a retest and keep those level within range.
Thanks for your reply PurpleNails! Really interesting about your TSH!
I used PTU in the first trimester and my endo switched me to carbimazole in my second trimester as it’s supposed to be safer to use in second but not in first.
Yes I’ve got another retest in two weeks so I think I’ll stick to the 2.5 mg then see how my levels are then. I don’t think she’ll listen to me about the unreliable TSH! But I’ll give it a try .
Carbimazole works by stopping iodine being converted to a usable form for the thyroid to make new T4 & T3. It doesn’t impact on pre-existing hormone. This is said to be up to an 8 week process. So a dose tweak now doesn’t fully manifest until later on, by which time you could have made another adjustment!
She tests me every six weeks. I have two weeks left until my next blood test. So this tweak I have done will probably not show up in the next blood test then I presume as I’ve only changed it in the last couple of days. .
I will definitely have a chat with her but not sure if I’ll get anywhere 🙄
I would call the medical secretary for the endo and ask them to check with endo, or your GP who can contact them for advice. My endo mentioned something about switching to some other med for hyperthyroidism if I plan pregnancy, definitely do speak to your doc first before making any changes yourself - they are the ones monitoring you over pregnancy, I don't think anyone would advise stopping any meds until you consult with the doc first!
Yes I was on PTU in first trimester but they switch to carbimazole in second.
To be honest I don’t think my endo will listen to be. She’s very focused on my TSH and I worry I’ll slip more and more into hypothyroidism if I keep on the carbimazole but I will try speaking to her at my next appointment .
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