Thyroid UK
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TSH shot up when pregnant

Through not being able to conceive naturally I discovered amongst other issues (PSO and low sperm count) That I had an under active thyroid TSH 13. My doctor started me on liothyronine and got my TSH down to 3.4 with a 75g dose which is within guidelines. However the ivf clinic said we could not do the egg transfer unless my TSH was under 2.5 as it will cause a miscarriage. My doctor upped my dose to 100g and my TSH dropped it within 2 weeks to 1.7, it then continued to drop and went to 0.13 which was causing my heart to race. So my doctor told me to alternate between a dose of 100 and 75 everyday. While all this was happening we had the egg transfer and I found out it worked and I'm now 3 weeks pregnant. I just had another blood test and my doctor just rang me very concerned as my TSH has shot up to 10! I had told her the ivf clinic said I needed to be under 2.5. She has told me I can increase my dose to 125 or 150 what ever i feel i need ??!! She is not a ferity expert so I thought I'll ring the ivf clinic and ask them what my TSH level needs to be when pregnant and is it normal for my TSH to have shot up like that. They won't help me at all, they now won't even confirm that it needs to still be under 2.5 just keep saying speak to my doctor. I so worried I'm going to harm our baby. I started on 125g this morning and booked in for a blood test in 2 weeks. I'm scare 150 will be too much but getting from 10 to 2.5 is a big jump.

7 Replies

Sorry meant to say im on levothyroxine

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Stick on 125mcg and make an appointment to see GP on Monday. As you say increasing to 150mcg is big jump

Clutter can advise. I think standard recommended increase is 25mcg after conception

You perhaps should be referred to endocrinologist

Have you had vitamin D, folate, ferritin and B12 tested? If not get them done ASAP too

What supplements do you take?

Do you have Hashimoto's, diagnosed by high antibodies. If so low vitamins are likely.

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It is 25-50mcg or 30%-50% increase when pregnancy is confirmed.


Yes, the lady from fertility clinic was right. You need to keep your TSH low to keep the pregnancy and avoid future problems with the baby.

You're not goin to hurt your baby if your TSH is low but within the ranges.

I could not get pregnant due to packed up thyroid during my 30 and misdiagnosed throughout all those years.

Please, please make sure you read on this. There are articles online. Make sure you do your bloods as often as it is possible to monitor possible changes in tsh. Your GP possibly won't be much of help.

I've learned why I couldn't conceive years later from foreign Endo doctor. Those doctors I saw in UK didn't know thyroid and pregnancy relevance.

I so want you have a healthy baby and wish you successful pregnancy and healthy, beautiful baby.

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TSH >2.5 increases the risk of miscarriage and NICE recommends increasing dose by 30-50% when pregnancy is confirmed so I would increase dose to 150mcg to bring down your TSH quickly.

Management of primary hypothyroidism: statement by the British Thyroid Association Executive Committee

The serum TSH reference range in pregnancy is 0·4–2·5 mU/l in the first trimester and 0·4–3·0 mU/l in the second and third trimesters or should be based on the trimester-specific reference range for the population if available. These reference ranges should be achieved where possible with appropriate doses of L-T4 preconception and most importantly in the first trimester (1/++0). L-T4/L-T3 combination therapy is not recommended in pregnancy (1/+00).

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Thanks everyone. After so much googling I think I found another reason why it shot up to 10. I was taking pregacare tablets that contain iron, half an hour after my levothyroxine. And for breakfast having flax seeds with my cereal. I read you shouldnt take iron or calium for 4-6 hours after levothyroxine as it stops it being absorbed. And that flaxseed stops the natural production of the thyriod hormone. So I'm quiting eating flaxseed and moving pregacare tablets to much later in the day.

Now my only concern is if I should take 125 or 150. I read there are equal dangers with dipping my TSH before 0.

I've got a blood test booked again for 2 weeks time. Maybe I alternate between 125 and 150?

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I took 125 yesterday and 150 today, think I'll continue to alternate days like that. I'll see how my body feels today I know from before that if I dip below 0 my heart races so hopefully I can judge it that way. Thank you everyone again for your support

TSH 10

T4 13

Thyriod peroxidixe Antibodies 352


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