35 Weeks pregnant - no thyroid - need help with results.

[nothyroid_22]

I was wondering if someone could help me. I'm 35 weeks pregnant, no thyroid and currently taking 200mcg levothyroxine. Earlier in the pregnancy, my levothyroxine dose was reduced to 150mcg which resulted in my t3 and t4 going down and I felt dreadful. Despite my tsh being low, the doc put me back up to 200mcg and feel really well but my tsh is 0.05 (t3 is 4.2 and t4 is 12.1). Is there any risks with my tsh being so low?

[Hidden]

nothyroid,

Sorry to hear you are having a worrying time during your pregnancy.

Hormones do go up and down throughout pregnancy but the important thing is to keep TSH LOW.

As your oestrogen levels go up with pregnancy, so does thyroxine binding globulin (TBG) that binds with T4 and lowers thyroid hormones. Your pituitary responds by producing far more TSH (thyroid stimulating hormone) which will increase your FT3 and FT4 to equal things out.

The placenta secrets high amounts of a hormone called human chorionic gonadotropin (HCG) which also stimulates the thyroid similar to the TSH.

Treatment for hypothyroidism should be increased during the pregnancy. Your GP should have followed specialist advice regarding your levo dose and TSH & thyroid hormone levels monitored regularly to keep TSH in low-normal range (0.4–2.0 mU/L) and FT4 in the upper reference range.

I wish you & baby well

Flower

cks.nice.org.uk/hypothyroid...

(Edited -link updated.)

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Disclaimer: I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.

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[Clutter]

Nothyroid_22, no problem with low TSH, it's high TSH which can be a problem.

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I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.

[jimh111]

You haven't given reference intervals but it does look like your TSH, fT3 and fT4 are all low which looks like a mild form of 'isolated thyrotropin deficiency'. This occurs when the TSH is lower than it should be for given fT3, fT4. The lowish TSH can reduced T4 to T3 conversion. Your fT4 is quite low given you are on 200 mcg L-T4. This could be because you are not absorbing it well, perhaps due to a gastrointestinal condion or if you have coffee around the time you take your L-T4. I would get your doctor to adjust your dose such that your fT4 stays in the upper half of the reference interval (and most importantly you feel well) regardless of the TSH.

[nothyroid_22 in reply to jimh111]

Thanks for this, it's really helpful. What is the upper range for ft4? would you know if there's any increased risks for delivery of baby?

[jimh111 in reply to nothyroid_22]

Normally the upper 95% reference limit for fT4 is about 20 but it varies between labs. Guidelines state that the TSH should be kept below 2.5 for the first trimester and then below 3.0 for the rest of the pregnancy (I'm going from memory). However, this assumes the pituitary is functioning optimally. These recommendations are to minimise any risk, which in any event is low. I don't know of any risks during delivery, I haven't heard of any although I don't have knowledge of this aspect.

[nothyroid_22 in reply to jimh111]

Thank you for that, it's good to know.

[Hidden in reply to jimh111]

jim,

Could T4 be low due to a raise in TBG ?

TSH is low.

Flo

[jimh111 in reply to Hidden]

Maybe, I don't have knowledge I this area.

[Hidden in reply to jimh111]

jim

During pregnancy (or the first phase of perimenopause), oestrogen rises and encourages higher levels of TBG.

High TBG binds more T4, lowering FT4 levels.

For this reason (& others), it is imperative to increase thyroid meds to keep hormones balanced.

Flower

[nothyroid_22]

I have been told I'm under consultant led care for delivery now and I just don't understand fully why.

[Hidden in reply to nothyroid_22]

nothyroid.

I would assume it is because you have had a TT and are medicating thyroid hormone replacement. The consultant will ensure you are well looked after, so minimising any risk of possible complications.

I am sure you will be well looked after nothyroid.

Best wishes to you both.

Flower

[nothyroid_22 in reply to Hidden]

Thank you that's reassuring. I've really struggled to understand whats going on but feel better from hearing from you all.