Thyroid UK
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subclinical hypothyroidism


I am pregnant at week 12+6.

The test results are

FT4 = 1.15

TSH= 4.61 (doctor said it is slightly high, the normal should be less than 2.5)

TPO= Negative

The doctor gave me a medicine. I started taking the medicine at week 12.

I am worried about my baby's intelligence abilities.

Are the test results high and how about my baby's health?

Thank you for help

4 Replies


Up until 12 weeks the foetus is dependent on maternal thyroid hormone so the foetus was probably taking from you and that is why your thyroid levels dropped and TSH became high. TSH 4.61 is a little high but may not have affected your baby's development.

For maximum absorption Levothyroxine should be taken with water 1 hour before, or 2 hours after, food and drink, 2 hours away from other medication and supplements, and 4 hours away from calcium, iron, vitamin D supplements, magnesium and oestrogen.

It takes 7-10 days for Levothyroxine to be absorbed before it starts working and it will take up to six weeks to feel the full impact of the dose. Symptoms may lag behind good biochemistry by several months.

You should have a follow up thyroid test 6-8 weeks after starting Levothyroxine. Arrange an early morning and fasting (water only) blood draw when TSH is highest, and take Levothyroxine after your blood draw.

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Was the medicine levothyroxine? and what dose? I should think your dose is about 50mcg.

Others who know more than me re pregnancy will respond but I think it's good doctor has prescribed.

If it is levothyroxine you take it first thing on an empty stomach with one full glass of water and wait about an hour before eating. Food and coffee or caffiene interferes with the uptake of thyroid hormones. That's why we leave an hour's gap.

The blood tests should be at the very earliest possible (they should be every six weeks until you are symptom free and a TSH of 1 or lower. Allow a gap of 24 hours between your last dose of levo and the test and take afterwards. Always get a print-out with the ranges for your own records and you can post if you have a query. If doctor didn't test for thyroid antibodies ask for this to be done next blood test.

If GP hasn't test B12, Vit D, iron, ferritin and folate ask for these at the next blood test.

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Just to let you know

I was terribly hypothyroid during my first pregnancy which was never picked up or treated and other than going overdue and a very difficult delivery (mal positions are linked to low thyroid) I have a very intelligent little girl who is top 3 in her class

However did suffer from slight delays until age 4

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That's a very helpful response and most mums-to-be would be very apprehensive. :)

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