
Hello Doctor! These 4 Questions Are On Behalf Of My

These 4 questions are on behalf of my niece who was diagnosed with Hashimoto’s Thyroiditis in 2018. I wanted to add that when I first found out about the diagnosis, I started taking low doses of iodine and selenium, and that helped to increase my FT4 and reduce my thyroid antibodies. I am still taking these supplements.
Here are my 4 questions:
(1) Why has my TSH always been normal, despite having low fT3 and fT4 levels? Could I have a pituitary issue that is preventing the release of TSH?
(2) Why has my FT4 decreased substantially since October, despite an increase in my thyroid medication?
(3) Is it dangerous to the fetus if my FT4 levels remain low, or should I increase my dosage again?
(4) Are there any other protocols that you would recommend that I follow in order to increase my thyroid hormone production?
History:
Since the time of diagnosis, my TSH has stayed normal (between 1 and 2 mU/l) despite my FT3 and FT4 levels being below the limits. I didn’t have any symptoms and didn’t take any medication, and managed to get my FT4 into the reference range through diet and supplementation. However, my FT3 remained below the reference range.
In August 2020, I started taking Natural Dessicated Thyroid extract, which is a combination of T3 and T4. I did not take L-thyroxine, as it is purely T4 supplement, and it was pointed out to me that I have a T4 to T3 conversion problem, not a T4 problem, as my FT4 was in the normal range. I also found out that I became pregnant in August.
I have increased my dosage twice since the start of the pregnancy. My results from the past few months, along with the reference ranges, are listed below:
Reference values:
TSH: 0.5-4 mU/l
FT3: 2.3 – 4.1 ng/l
FT4: 9 - 17 ng/L
Test results:
Date: 14.10.20
TSH = 0.61 mU/l
FT3 = 3.3 ng/l
FT4 = 12.4 ng/l
Date: 17.12.20
TSH = 0.63 mU/l
FT3 = 2.56 ng/l
FT4 = 8.5 ng/l
After finding out that my FT4 was below the reference range, I increased my NDT dosage from 3⁄4 grain to 1 grain on December 26th, 2020
Date: 14.01.21
TSH = 0.66 mU/l
FT3 = 3.26 ng/l
FT4 = 7.9 ng/l
I wanted to add that when I first found out about the diagnosis (Hashimoto's thyroiditis), I started taking low doses of iodine and selenium and that helped to increase my FT4 and reduce my thyroid antibodies. I am still taking these supplements.
Isolated maternal thyroxinemia
Detailed Answer:
Hello
I have gone through your query and understood your concern.
Hashimoto thoridism is the most common thyroid autoimune disease and the most common cause of hypothyroidism.
In this condition the test results show high level of thyroid antibodies ,high TSH level and normal or (most frequently)low thyroid hormones fT3 and fT4.
You have high thyroid antibodies and this confirm the diagnosis of Hashimoto's thyroiditis.
The only problem that i see in your results is a slighly low thyroxine level(low fT4).
In my opinion you are a case of Isolated maternal thyroxinemia.Iodine deficiency is the most common cause of this condition for this reason,i agree with iodine and selenium supplementation.
I'm sure that you know that during pregnancy all the maternal metabolism change or there are specific/essencial adaptions to meet the physiological demands of pregnancy as well as adequate growth and development of the fetus.
Even the thyroid physiology and metabolism change because the demands on the maternal thyroid significantly increase during pregnancy.
At the other side ,In pregnancy, there are a number of changes in the thyroxine-binding proteins that affect results of FT4 measurements.
For this reason,it is recommended to use method-specific and trimester-specific reference ranges of fT4 and fT4.
1- you have not a pituitary disease that cause low fT4.In secondary hypothyroidism the pituitary gland do not produce enough TSH hormone and in that case you shoud have low TSH,and low thyroid hormones.This is not your case.
2. FT4 levels measured with immunoassays gradually fall as pregnancy progresses for this reason i suggest you may have Isolated maternal thyroxinemia.
3.-mainatain normal thyroid hormone levels in very important for fetal neurodevelopment for this reason i think you may need a slightly dose adjustment of your thyroid hormone therapy.
4-If you were my patient i would recommend to switch to levothyroxine.I don't think you have a T4 to T3 convertion problem because this is a familiar genetic and rare disease.
Hope a have clarified all your doubts.
Wish you good health.


Leroy
Ok.
Detailed Answer:
I appologise for the late reply.
If you have other doubts,feel free and ask.
Wish you all the best.


(1) Could you please explain why my TSH has always been in the normal range, despite low ft3 and ft4? This was even the case before my pregnancy.
(2) Is ft3 more important than ft4, since most of the t4 gets converted to t3? Before I started medication my ft3 was always lower than the limit, despite having a normal ft4. If I don't have a conversion problem, could you please explain why the t4 is not getting converted to t3?
Thanks in advance.
Low FT4/
Detailed Answer:
Hi again
I have carefully gone through your thyroid test result,in order to understand better/.
As i said earlier,considering the normal ranges of your lab,the only problem that i see in your test results ,is a slighltly low fT4( in december and january )with normal TSH and normal ft3 levels.
Test results in october -everythink in the range.
The diagnosis of Isolated maternal thyroxinemia can be the explanation of these test results and the progression of fT4 level during the months of pregnancy correlate with this diagnosis.
If you had a isolated TSH deficiancy or a pituitary problem,than you will always have low TSH and consecutively low fT3 and ft4.But this is not your case because you have normal TSH level.
Both fT3 and fT4 are important but fT3 is the active form that give the effects in all the tissues of you body.
Considering all your thyroid test results during the months , you have low fT4 and normal fT3.
The active forme of thyroid hormones that is responsable for the thyroid hormone effects in your body is normal.
sh you good health
Your T4 to T3 conversion in OK.
Your low fT4 do not produce a low Ft3,so this i do not see a convertion problem at all.
I recommend to repeat the thyroid hormone panel every month during the pregnacy.
Let me know the results in a Direct query or a Video consultant and i will be happy to guide you further.
Wish you good luck.
Bringing now life into the world is nor easy.
Hope i have clarified all your doubts
If you are Ok with the answers,please close the question.
Bringing new Life into the World is not easy.
Wish you all thye best.
Dr Elona

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