Tsh blood test whilst pregnant

[nettiboo1982]

hi I've got too have my first tsh blood test since getting positive home test. But I'm really anxious too not take my dose for the test as I take my levo at 11pm at night so id miss over 24 hours without a dose. Can I just take it as normal and have test will it make that much difference? Thanks

[jimh111]

You should not leave long periods between taking thyroid medication and blood tests, it distortes the results.  As long as you don't take medication within a few hours of the blood being taken then it is fine.  Taking your levothyroxine the evening before is perfect.

[nettiboo1982]

I thought the common thing was too fast and too not have taken your levo that morning. I usually miss my evening dose before a blood test but then I'm not normally pregnant

[shaws Administrator in reply to nettiboo1982]

These are two excerpts from a previous post (3 years ago).

1. "I take my levothyroxine at bed time. But when I am going for a blood test, I defer that until after the blood draw in the morning. One reason I always try to get that blood draw done as early as possible.

"

Rod

2. "I  have asked myself the same question and understand where you are coming from with this. However, my GP (not that he is much good at anything) also told me not to take my meds on day of the test because it temporality raises the circulating levels of thyroid hormones in the blood." 

healthunlocked.com/thyroidu...

From another link:

Thyroxine has a half life of 6-7 days 

What does this mean.. if you are normal it takes 6-7 days after ceasation of hormone treatment to drop to 50% blood concentration after equilibrium was achieved.. then another 6-7 days to reach 25%.. and another week to reach 12.5%.. etc.

healthunlocked.com/thyroidu...