Thyroid and Pregnancy

[Kay113]

I am 6 weeks pregnant and have been diagnosed with Hashimoto's thyroiditis. I have one live child and have had 2 miscarriages over the last year. As you can imagine I am quite nervous about this pregnancy. I did not carry past 6 weeks in either of my 2 miscarriages. My question is regarding Synthroid dosages. Prior to pregnancy I was on .088mg which was a little high for me so I went back down to .075mg, now that I am pregnant I had my TSH checked at 4 weeks gestation and it was 4.5 and my OB said it was in normal range. I started feeling cold intolerance and my hair has been falling out so I bumped up to 0.088mg again and am having some issues with nervousness and racing heart at times. Could this dose be too high and be causing me to be hyperthyroid that quickly? I don't want to miscarry again and I know that hyperthyroidism can cause that. Also, I am using 300mg of Progesterone suppositories daily to help maintain the pregnancy, could this have any affect?

I appreciate any help!

[Mark Lupo, M.D.]

TSH usually decreases in first half of pregnancy (in patients without thyroid disease)

In your case the target TSH is no higher than 2.0  and it is better to have a slightly low TSH (0.1-0.4) than a slightly high TSH.  The increase to 88mcg was the right step - some people are sensitive to changes, esp in first 10-14 days so this may be why you had the symptoms, but keeping optimal levels during pregnancy is very important.

Would watch levels every 5-6 weeks and keep adjusting synthroid as needed.

Progesterone should not influence thyroid levels significantly.

[Super_sally888]

Hi Kaye,

Do you have an endocrinologist?  You need to see one urgently if you are pregnant to make sure everything is well regulated.  4.5 is no longer in normal range, but slightly outside it.  Your OB may not be up to date.

TSH of 4.5 is actually high for pregnancy.  Normal target would be around or a little less than one.  I doubt that you could go hyper with such a small dose increase.  Anyway slightly hyper during pregnancy is far safer than being hypo.

I am now 13 weeks pregnant with hypothyroid. We test my thyroid levels monthly and try to keep the FT3 and FT4 in top 25% of normal range. I've had one increase in thyroid meds and am expecting another soon.

My doc told me that they don't look at TSH during pregnancy other than for screening - but rather FT3 and FT4 for control of thyroid levels because the pregnancy hormones can interfer with the TSH test.

Hope this helps.  Doc Lupo will give you a good answer I'm sure.

Sally

[Kay113]

Thank you so much for your help! Your post has raised a couple of other questions that I am curious about. First, how does pregnancy affect TSH? I know that HCG stimulates the thyroid but not sure what that causes TSH to do. Also, I have heard conflicting info on when an increase in Synthroid is usually needed. Some sources say usually in 1st trimester and others say not until the 2nd.

Thanks again!

[Super_sally888]

Hi Kaye,

The tsh and pregnancy question is very complicated.  I found some stuff on line, but can't really explain it.  however, I understand that TSH may be supressed during pregnancy which is why they also look at the other parameters, and also keep the TSH at the low end of normal.

When to increase thyroxine is very individual.  Given your TSH is 4.5 you would need an increase already.  My doctor tests every month.  I had my first increase about week 8 of pregnancy.  My doctor expects further increases - he says 25 - 40% increase overall - during the rest of the pregnancy.

Hope this helps.

Sally

[ar1281a]

Dr Lupo has posted before what's the preferred TSH level for conceiving and during pregnancy. Look it up, but I believe he says it's around 0.3-2.0, where lower is preferred. He cites some recent guidelines issued.

You also need to keep an eye on your antibodies. Go see your endocrinologist and get checked as your thyroid should be monitored closely. Good luck!

[paj_yeeb]

hello there..well, i just wanted to tell you that i'm hyperthyroid and pregnant...i've read alot of things about thyroid problem and it scare me alot. everynight i pray that my baby will be ok..and this was my first pregnacy. my doctor had told me that being hyperthyroid can cause affect to the baby. when he told me this it hurt me sooo much. 9 months later i gave birth to a beauiful very healthy baby girl..she is perfect...don't let things like this hurt you, like it hurted me. have faith in your preganacy and everything will be ok. may god watch over you and good luck.