Subclinical Hypothyroidism
Do I Have an Underactive Thyroid?
The short answer to this question is ‘no’. However it is worth taking the time to understand what the thyroid gland is and what your blood tests really mean.
The thyroid is a gland that sits at the front of your neck and is responsible for making ‘thyroid hormone’. Thyroid hormone (also known as T4) is a hormone that increases energy production and activity in the body. Therefore people with a low level of thyroid hormone often feel tired. People with a low thyroid hormone level are said to have an ‘underactive thyroid’ (a condition also known as ‘hypothyroidism’).
Based on your blood results, your thyroid gland is making a normal amount of thyroid hormone. It is therefore not ‘underactive’ in this sense.
Your brain sends signals to the thyroid gland by producing a special hormone called ‘TSH’ (or ‘thyroid-stimulating hormone). Your blood results indicate that you have a higher level of TSH than usual. This essentially means your brain is telling your thyroid gland to make more thyroid hormone. This is called ‘subclinical hypothyroidism’.
Is Subclinical Hypothyroidism a Problem?
For the vast majority, it is not a problem at all, and in fact, it affects up to 10% of the population. Most people do not experience any symptoms because your thyroid gland is producing a normal amount of thyroid hormone. In fact, for most people, blood tests return to normal in about five years. In 2-5% of people, it can eventually lead to an underactive thyroid. That’s why it’s advisable that you monitor your thyroid levels every 2-3 years.
It can sometimes be more troublesome in pregnancy. Therefore if you are pregnant or planning on becoming pregnant very soon, please let your doctor know at the earliest opportunity, as you may need a referral to a hospital specialist (endocrinology).
What Do I Do Now?
If this is the first time you’ve had a blood test which shows subclinical hypothyroidism, we would recommend that you repeat your thyroid blood test in 3-6 months time. This is to check that your thyroid levels are not changing in any way and also to check a special antibody (TPO) that sometimes appears in people with thyroid disease. If this test is abnormal, your doctor will let you know.
What Do I Do if My Second Blood Test is Still Showing Subclinical Hypothyroidism?
This is expected and as long as your thyroid levels are stable, there is often nothing more to do for now. However, you will need to ask your doctor to request another thyroid blood test in 2-3 years. You will not be routinely contacted about this so make sure you make a note to arrange this when the time comes.
Do I Need Treatment for This?
Evidence suggests that thyroid hormone replacement does not improve symptoms, mood, or quality of life in people with subclinical hypothyroidism. We can be mindful however that there is a 2-5% future chance of progression to an underactive thyroid so let your doctor know if you develop any of the following symptoms: significant tiredness, long term and unresolving constipation, particular sensitivity to the cold, unexplained muscle aches, depression or weight gain. Thyroid hormone replacement can sometimes be trialled in subclinical hypothyroidism but we should be aware that symptoms of underactive thyroid can often be similar to symptoms of other conditions (such as menopause, depression etc.) so we should keep an open mind.
I am Pregnant or Planning a Pregnancy Very Soon
If you are pregnant or planning on becoming pregnant in the very near future, it is important to let your doctor know as we will likely need to involve a hospital specialist and start treatment.
Anything Else I Should be Aware of?
Please inform your doctor immediately if you start to experience any pain, swelling or lumps at the front of your neck, or if you experience any unintended weight loss, loss of appetite or night sweats. This can indicate more serious thyroid disease which would need to be investigated further.