Thyroid levels when pregnant

[BenLabrador]

My GP daughter is expecting her first child in May. The results of her thyroid function test are T4 10.3, normal range 11.0 - 21.2 pmol/L, and TSH 1.87, normal range 0.27 - 4.20 mIU/L.

She understands that these results are normal in pregnancy and an obstetrician has said she does not need T4 prescribed.

Given my experience of being told everything is ‘normal’ when I have been unwell, leading me to self-source T3 and test privately, I am suspicious of anything the NHS says is normal regarding thyroid issues. And it concerns my grandchild.

I’d be grateful for your opinions.

[humanbean]

Before your daughter became pregnant was there any evidence that she might have been hypothyroid? If yes, what were her symptoms and any recent test results?

Does your daughter have any symptoms of hypothyroidism now? How does she feel?

It is extremely annoying that the NHS doesn't test Free T3, particularly since T3 is the active thyroid hormone. Do you have any results for Free T3 in recent months?

Some links you might find useful :

patient.info/doctor/thyroid...

btf-thyroid.org/pages/searc...

pmc.ncbi.nlm.nih.gov/articl...

pmc.ncbi.nlm.nih.gov/articl...

library.wmuh.nhs.uk/wp/libr...

liebertpub.com/doi/pdf/10.1...

endocrinologyadvisor.com/ne...

pmc.ncbi.nlm.nih.gov/articl...

niddk.nih.gov/health-inform...

[BenLabrador in reply to humanbean]

Thank you for this and the links. She did not, and does not, have any symptoms and is feeling fine. She hasn’t been troubled by her thyroid in the past. All new, and I don’t know if it’s a problem now or just a normal result of being pregnant.

[greygoose]

Her FT4 is below range. That is never 'normal' for anyone - especially not a pregnant woman. I would have thought she needed to be prescribed levo as a matter of urgance. But I suppose he was only looking at the TSH!

What time of day was this the blood draw for this test? Were antibodies tested. What is her GP saying about all this?

[BenLabrador in reply to greygoose]

Thank you Greygoose. I have sent her your reply.

[greygoose in reply to BenLabrador]

Your wecome.

[Hedgeree]

Hi BenLabrador,

With your daughter being a GP would she possibly be able to find an informed colleague with knowledge of hypothyroidism?

I would be inclined to do a private blood test around 9am as often recommended on the forum so she knows what her TSH, FT4, FT3 and antibody levels are then post them on the forum for others to comment.

[BenLabrador in reply to Hedgeree]

Thanks for this Hedgeree.

[Tina_Maria]

Adequate thyroid levels are important in the first trimester of pregnancy, as the developing baby relies on the thyroid hormones from the mother. The baby starts to produce thyroid hormones from around 12 weeks but still relies on the maternal supply until week 18 or 20. So by now your grandchild should be able to produce its own hormones.

niddk.nih.gov/health-inform...

There can be fluctuations in T4 hormones in pregnancy, as levels of oestrogen increase. Oestrogen can increase levels of thyroxine binding globulin (TBG), which in turn can reduce levels of free T4. The placenta also contains an enzyme (deiodinase), which can increase its activity through an increase in metabolism, which can metabolise the T4.

Although the TSH looks 'normal', the T4 below the reference range should definitely be looked at. And given the family history of thyroid disease, I would perhaps insist on repeating a full thyroid test (and maybe test antibodies as well) in a couple of weeks, so it can be established if it was a 'one off', or if there is a pattern.

[BenLabrador in reply to Tina_Maria]

Thank you for this. Much appreciated. I have sent your reply to her.