Dear Elaine,

I am 31 years old and is now 23 weeks pregnant (for the first time) and is currently diagnosed with hyperthyroidism.

Because I am pregnant, I am so worried that the disease would affect the health and growth of my baby. I would be grateful if you could help provide me advices to recover from it as soon as possible.

Here is my story.

On December 11, 2011 during the first doctor visit of my pregnancy (at 8 weeks), I was told to have my thyroid hormone values, FT4, FT3 and TSH, checked (because I used to have thyroid problem many years ago (* read below)). Here are the results of the thyroid related test.

- Dec 12, 2011 (8 weeks)
FT4: 1.82 ng/dl (N: 0.71-1.85)
FT3: 4.2 pg/mL (N:1.45-3.48)
TSH 3rd Generation: 0.051 muUI/mL (N: 0.47-4.64)

- Dec 17, 2011 ( 9 weeks), results at a different lab to verify
FT4: 24.0 pmol/l (N: 9.2-23.9)
FT3: 5.12 pmol/l (N:2.22-5.32)
Ultrasensible TSH: 0.05 mUI/l (N: 0.49-4.67)

- Dec 22, 2011 (9 weeks)
Thyroid ultrasound checked. There were many tumors. Large ones have the diameter of 6x4, 8x5, 12x6 (mm x mm).

- Jan 14, 2012 (13 weeks)
FT4: 2.32 ng/dl (N: 0.71-1.85)
TSH 3rd Generation: 0.005 muUI/mL (N: 0.47-4.64)
TSH Receptor: 0.3 UI/L (N: <= 1.0)
Anti Microsomal (TPO Ab): 5 UI/ml (N: <34)

- Jan 17, 2012 (13 weeks)
I was diagnosed as having a sub-clinical hyperthyroidism.
I was prescribed: PTU 50mgx2, twice a day, morning and evening, and I started taking it.

- Feb 3, 2012 (16 weeks)
FT4: 17.4 pmol/l (N: 9.2-23.9)

- Feb 5, 2012 (16 weeks)
The Endo changed the PTU dosage to: 50mgx1, once a day, morning only.

- Feb 23, 2012 (18 weeks 6 days)
FT4: 12.7 pmol/l (N: 9.2-23.9)

- Feb 24, 2012 (19 weeks)
I talked to my Endo that my FT4 value is getting lower and lower and I was worried it could affect the growth of the baby. But the Endo still asked me keep the dosage of 1 tablet of 50mg PTU a day.

I decided to I stop taking PTU on my own on fear my thyroid hormones will become too low if I continue to take it.

I took a test to see the values one week later and 4 weeks later.

- Mar 2, 2012 (20 weeks)
FT4: 12.9 pmol/l (N: 9.2-23.9)
FT3: 2.9 pmol/l (N: 2.22-5.32)
Ultrasensible TSH: 0.03 mUI/l (N: 0.49-4.67)

- Mar 23, 2012 (23 weeks)
FT4: 11.9 pmol/l (N: 9.2-23.9)
FT3: 2.39 pmol/l (N: 2.22-5.32)
Ultrasensible TSH: 0.06 mUI/l (N: 0.49-4.67)

Was I treated correctly with the dosage of PTU from the beginning? Was it wrong that I stopped the medication?
Now I am not taking PTU any more, but why do FT4 and FT3 values continue to drop? What should I do?
What should I do to treat it without doing any harm to my baby.
I do appreciate your advice on my health problem.

Sophia


Note:
(*) About 7 years ago when I was about 24 years old and was a student in Japan, my thyroid gland became swelling which slightly hurts when I swallowed something.

I visited a hospital and took blood test and ultrasound. I only remembered my FT4 value was abnormal. Doctor told me there was a tumor in my thyroid gland; it may be benign or it may not. It may be the grave disease.
I think at that time my FT4 value may be low because he told me that the disease could affect my IQ and asked me whether my country borders the sea. Why I could have the thyroid problem...

He did not prescribed me any medicine. He continued to monitor my FT4 value and thyroid ultrasound for a period of about 6 months, if I remembered well.
The tumor gradually disappeared and the FT4 returned to normal value. He told me I completely recovered and no need to follow up with the disease any more.

About 6 months or one year later, I insisted to have my thyroid gland ultrasound checked and the FT4 value checked again. The result was completely normal.

With less knowledge on this disease, I thought I have completely recovered and never checked it again until I am pregnant.