Thyroid UK
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Try to conceive, hypothyroidism, Levothyroxine

two months ago, found my TSH was 5.1, FT4 16.8. read on Internet that hypothyroidism can affect fertility. Upon request, GP prescribed Levothyroxine 25 microgram. On the medicine for 4 weeks and blood test showed TSH 0.4 and FT4 17.6.

I am just wondering whether the drop of TSH was too sharp? Is the dosage a bit too high? GP has no knowledge and didn't even want to treat me. I have asked for a referral to an endo. But will have to wait for a few months for the appointment.

I am halfing my dosage for now. Has anyone got similar experience? Do you adjust dosage by yourself?

9 Replies

25 mcg is the minimum .....its safe just to drink it if you dont need it :) you would feel it if you dont need it...TSH is at this point almost irrelevant

to concieve is just step 1 there are many steps and possible problems after... if you dont have regulated thyroid.....unf i had a friend who lost her baby in 6th month of pregnancy....her thyroid was not good and she did not know!


I wouldn't adjust your dosage yet as you might mess up your metabolism particularly if you want to get pregnant. 25mcg is an extremely low dose. I will try to see some links re pregnancy or someone who knows will reply. Levothyroxine is a hormone and usually doctors will not prescribe unless your TSH is 10, some will if it is around 5 if you have symptoms so you were lucky.


This is one link and your TSH was too high to get pregnant and if you are not looked after properly, some women miscarry. Some aren't even aware they are hypothyroid. I think your GP was wise to medicate.

When you post your blood test results, it is helpful if you can put the ranges as labs differ and it makes it easier to comment.

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Hi Shaws

Thank you very much for your reply. It's very helpful!


This was an earlier post which may interest you.


xjww, TSH in the low normal range 0.4-2.0 is recommended for women trying to conceive or newly pregnant. Meds are usually raised by 50mcg as soon as pregnancy is confirmed to ensure good foetal development and avoid miscarriage.

These are the NICE guidelines

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Thank you, Clutter

Looks like the blood test should be done very 4 weeks to start with.


Hi xjww,

I've had Hashimoto's for over 9 years and I do adjust my medication levels myself (only by 25mg at a time), though I had been on Thyroxine for a number of years before I started doing that. I'm also 29 weeks pregnant and had suppressed TSH levels when I fell pregnant but my TSH levels and medication dosage had been stabilised for at least 6 months before we tried for a baby.

Are you feeling symptomatic, or just wanting to change your dosage because of your TSH reading? From memory a FT4 reading of 17.6 is still within the normal range and my understanding has always been that the FT4 and FT3 levels are more important than the TSH.


Hi Ozgal

Thank you very much for your reply. I felt palpitations at bed time. Rapid heart beats every so often when I tryied to sleep. I am wondering whether it was caused by over dosage. Also, my friend who has got Hashimoto's told me her TSH was reduced from 4 to 2 and then to 1 over the period of a few months. While mine went from 5 to 0.4 in 4 weeks. This also makes me worry if I am taking too much medicine.

My other indices are within the normal range. No antibodies. Only my TSH tends to fluctuate between 3 and 7. I heard you need to keep it below 2 if you were to try to conceive.

Do you go to see an endocrinologist to treat your hypothyroidism or do you go to see your GP?

How often did you do your blood tests when you were trying to establish the correct dosage for you? My GP were very relucant to repeat the blood test once every 4 weeks. I kept getting told I can only repeat the blood test once every 3 months, otherwise it is misleading.

Also, how did you get your FT3 tested in the UK? My GP only tested my TSH and occassionaly FT4. Once I requested FT3, the lab sent the blood test form back and refused to do the test. I only managed to get a full Thyroid profile blood test done in a foreign country -_-!


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