Thyroid UK
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Increased Levothyroxine during pregnancy @ 5wks shouldn't your levo be increased by at least 25mcg?

I'm on 75mcg Levothyroxine a day, diagnosed about 10mths ago when my son was 7mths old. I'm only 5weeks pregnant but guidelines state that Levothyroxine should be increased by 25-50mcg to ensure minimal adverse effects on fetal development. Can anyone offer any further advice on this? I've spoken to two doctors at my clinic and neither have suggested increasing my dose or requested blood tests. Fortunately I had some blood tests outstanding so should get results next week.

5 Replies

Yes, you definitely need to get your thyroid tested every trimester. You may or may not need an increase in dose, which is why the blood tests are so important. I didn't need an increase with my son but I did with my daughter. Also go by how you feel. If you are getting symptoms of hypothyroidism then see your doctor straight away.

As well as taking your folic acid, make sure you are also getting at least an equal amount of B12. The two work together and are very important for neurological development and health :)

I hope that helps

Carolyn x


Thank you I have been getting regular headaches everyday for over two weeks, I could fall asleep at 4pm most days. I was taking folic acid, b complex, selenium and q10 supplements but have now swapped for the pregnancy multivitamin which has folic acid and b12 as you suggested. It's hard to judge symptoms as I felt this tired last time when I was pregnant. It's good to hear that I may not need to increase my dose. I'll keep an eye on my test results though. Thanks again, Elaine


The minute you feel you might need an increase, please do see your doctor. If you notice a change in your blood tests this time, that will also indicate if you might need an increase. Hope it all goes well :)


This is from the British Thyroid Association



Headaches can be a hypo symptom for me. Please post your results on here when you get them and hopefully someone will comment. Xx


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