Do TSH levels naturally increase during menstruation?

[sunshineisbetter]

I had my last blood test on the first day of my period which showed my highest TSH level so far. I was wondering if this was a coincidence or not?

[jimh111]

See Figure 1 ncbi.nlm.nih.gov/pmc/articl... . There are big variances during the cycle although I've no idea when day 1 or day 14 is!

[sunshineisbetter in reply to jimh111]

I don’t fully understand this article! Which day of the cycle is it actually saying TSH is at its highest?

[jimh111 in reply to sunshineisbetter]

It is saying TSH is highest mid-cycle (periovulatory days). It's not an easy study to follow, I think they could have written it up more clearly.

These two women were hypothyroid and so reliant on levothyroxine. If they were healthy an increase in TSH would have stimulated secretion of more thyroid hormone and so I would deduce that the rise in TSH will be smaller in healthy subjects.

I'm really not into menstrual cycles so doing my best to interpret it and open to correction.

[sunshineisbetter in reply to jimh111]

Thank you for the explanation!

[radd]

sunshineisbetter,

TSH is highest mid cycle along with many other biomarkers that no doctor seems to take any notice of 😁.

TSH rises in response to the oestrogen rise. Because our hormone feed back systems are so immensely sensitive, this TSH rise is a response to the TBG created in response to that rise in oestrogen. TSH is trying to encourage more thyroid hormone to equal that of the TBG which will bind it.

[sunshineisbetter in reply to radd]

Thank you. This is really helpful in terms of when I have my next test in terms of diagnosis. Does the contraceptive pill affect this? I take yasmin x

[radd in reply to sunshineisbetter]

sunshineisbetter,

I assume the rise to be insignificant. Otherwise it would be more advised on this forum because it isn't something new.

With regards to contraceptive pills, I don’t know. I was diagnosed post my days of taking contraception which despite trying several always made me feel ill anyway.

I guess it depends whether the contractive pill was a combo, ie oral oestrogen invites higher TBG (protein transporter) much like oral HRT or even after conception but O & P balance each other out so less likely to invite change. (Higher TBG binds more thyroid hormone, decreasing ‘frees’ so TSH is increased to encourage more thyroid hormone availability).