Thyroid UK
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Advice needed forDr Skinner's patient, 6 weeks pregnant on Erfa

Hi please can anyone advise us, my daughter has just found out she is pregnant, she is post RAI Graves patient on 3 grains of Erfa for the past 2 years. She was Dr Skinners patient so we have no support at the moment & all a bit of a muddle, not exactly planned! She has got a midwife early bird appointment on 30th Dec & has started folic acid but does anyone have any advice on dosage, at what stage would she need to increase her dose? Any advice or experience gratefully received from a very anxious Mum.

Thanks Debs

3 Replies

I can't advise on erfa as I don't take it, but I know it is normal to have a dose increase (of levothyroxine about 25mcg) at the start of pregnancy, so perhaps consider a small dose increase.

It amazes me how babies manage to grow and take what they need regardless of the 'state' of the mother. I managed to have 2 very healthy little girls while living on bread and water and vomiting daily, B12 deficient (found out later), undertreated hypothyroid, oh, and being nearly 40 too! Sounds like your daughter is on a stable dose and well in herself, which is a great start. I understand that if you treat yourself according to your symptoms there is no reason to worry. I wish I'd had the flexibility to do that for myself!


This is advice from Dr Toft, BTA.

Patients with hypothyroidism who become pregnant need to have the dose of levothyroxine increased on average by 50µg daily in order to maintain normal serum TSH concentrations.

The advice to patients with established hypothyroidism is that they should increase their dose of levothyroxine by 25µg daily as soon as pregnancy is confirmed and make an appointment for thyroid function tests to be measured some two weeks later. The aim is to achieve a free T4 concentration of 16-20pmol/l.

Further measurement of serum free T4 and TSH should be made six weeks later and again in the middle of the second and third trimesters.

The pre-pregnancy dose of levothyroxine can be restored four weeks after delivery by which time the increased concentrations of thyroxine binding globulin will have returned to normal. It’s not clear whether this meticulous care is necessary and it may well be that any thyroxine therapy in the hypothyroid mother will allow normal foetal development.

Dr Tony Toft is consultant physician and endocrinologist at the Royal Infirmary of Edinburgh, and a former president of the Royal College of Physicians of Edinburgh and of the British Thyroid Association


Hi Has she tried to see an Endo,? It is best to find a good one first and then ask for a referral. A general Endo deals in all these issues and a lot more beside.Who ever she sees it would be a good idea to phone their sec first and check they will keep her on Erfa. A lot of private ones would , not so sure about NHS ones.

Regarding the Folic acid, my daughter who was an R and D chemist until children. Says that the Folic acid has to be taken pre conception, not much use taking it after that. That is the latest research. You could find that, on a very reliable site on the WEB The Mayo clinic USA is the one the medics all use, not sure if that will be on or not

It is well know that pregnancy can alter the thyroid, so important to be under a good Endo..

Best wishes, to all,



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