Hi all,
I was supplemented with eltroxin after fertility testing where the doctor wanted to lower my TSH.
I had two tests after - 1 for booking bloods for pregnancy and 1 after we unfortunately miscarried.
What I noticed was while my TSH was lowered. My free T4 which started at 14 decreased to approximately 12
Is this normal for the free T4 to decrease as well?
Should I be asking for any additional tests?
Thanks for reading.
That can happen when you haven’t been prescribed enough levothyroxine. How much were you prescribed?
I’m so sorry to read about your miscarriage. x
Thank you Jazzw.
I am only on 25mcg - my TSH was borderline (just under 4) but the fertility specialist wanted it closer to 2.5. My TSH has gone down to about 2.2 or so.
I thought so. 
Levothyroxine isn’t a supplement—it doesn’t “top up” your own thyroid function, at least, not after the first couple of weeks. What tends to happen is that your brain senses the thyroid hormone in your system from the levothyroxine you’re taking and produces less than it did before you started taking it. So you end up more hypothyroid if you’re put on too low a dosage.
A starter dosage for someone young and in otherwise good health should be 50mcg, not 25mcg. As SlowDragon has said below, it’s best not to TTC until you’re on a stable and therapeutic dosage of levothyroxine.
Are you still taking 25mcg? With a TSH of 2.2, you almost certainly need a raise in dosage.
Yea still on 25mcg. I had a conversation with my aunt today (she is retired now but was head of a pathology lab and also has hypothyroidism ) she said the same thing to me that the dose is not great.
She was saying I should be probably on 75mcg. Hopefully I will get my dose raised on Monday - I and asked my gp to extend my prescription after the fertility clinic (we left them as we got pregnant naturally) and she was nervous to do so and only extended it by a month.
I’m guessing she may refer me to an endocrinologist instead.
Sadly extremely common for medics to think “a little bit hypo” only needs “a little bit of levothyroxine “....but it doesn’t work like that
Feed back mechanism means as soon as we take levothyroxine, pituitary in brain notices, stops shouting at thyroid to make thyroid hormones...
Thyroid takes a rest ....you can end up more hypothyroid that you started
Standard starter dose of levothyroxine is 50mcg and dose is almost always increased slowly upwards in 25mcg steps until on or near full replacement dose
TSH should be under 2 before TTC...
And on levothyroxine usually many endocrinologist would want TSH to be under one before TTC ....all four vitamins must be optimal too
As soon as conception confirmed, dose increased
Even if we don’t start on full replacement dose, many/most people need to increase levothyroxine dose slowly upwards in 25mcg steps (retesting 6-8 weeks after each increase) until on, or near full replacement dose
NICE guidelines on full replacement dose
nice.org.uk/guidance/ng145/...
1.3.6
Consider starting levothyroxine at a dosage of 1.6 micrograms per kilogram of body weight per day (rounded to the nearest 25 micrograms) for adults under 65 with primary hypothyroidism and no history of cardiovascular disease.
Also here
cks.nice.org.uk/topics/hypo...
gp-update.co.uk/Latest-Upda...
Traditionally we have tended to start patients on a low dose of levothyroxine and titrate it up over a period of months.
RCT evidence suggests that for the majority of patients this is not necessary and may waste resources.
For patients aged >60y or with ischaemic heart disease, start levothyroxine at 25–50μg daily and titrate up every 3 to 6 weeks as tolerated.
For ALL other patients start at full replacement dose. For most this will equate to 1.6 μg/kg/day (approximately 100μg for a 60kg woman and 125μg for a 75kg man).
If you are starting treatment for subclinical hypothyroidism, this article advises starting at a dose close to the full treatment dose on the basis that it is difficult to assess symptom response unless a therapeutic dose has been trialled.
A small Dutch double-blind cross-over study (ArchIntMed 2010;170:1996) demonstrated that night time rather than morning dosing improved TSH suppression and free T4 measurements, but made no difference to subjective wellbeing. It is reasonable to take levothyroxine at night rather than in the morning, especially for individuals who do not eat late at night.
BMJ also clear on dose required
Very sorry for your miscarriage
Important to be on high enough dose levothyroxine for levels to be stable BEFORE TTC
And very important to regularly retest vitamin levels and to test thyroid antibodies to see if you have autoimmune thyroid disease also called Hashimoto’s
For full Thyroid evaluation you need TSH, FT4 and FT3 plus both TPO and TG thyroid antibodies tested. Also EXTREMELY important to test vitamin D, folate, ferritin and B12
Low vitamin levels are extremely common, especially if you have autoimmune thyroid disease (Hashimoto's) diagnosed by raised Thyroid antibodies
Ask GP to test vitamin levels and thyroid antibodies
Recommended on here that all thyroid blood tests should ideally be done as early as possible in morning and before eating or drinking anything other than water .
Last dose of Levothyroxine 24 hours prior to blood test. (taking delayed dose immediately after blood draw).
This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip)
Private tests are available as NHS currently rarely tests Ft3 or thyroid antibodies or all relevant vitamins
List of private testing options
thyroiduk.org/getting-a-dia...
Medichecks Thyroid plus antibodies and vitamins
medichecks.com/products/adv...
Thriva Thyroid plus antibodies and vitamins By DIY fingerpick test
Thriva also offer just vitamin testing
Blue Horizon Thyroid Premium Gold includes antibodies, cortisol and vitamins by DIY fingerprick test
bluehorizonbloodtests.co.uk...
If you can get GP to test vitamins and antibodies then cheapest option for just TSH, FT4 and FT3
£29 (via NHS private service ) and 10% off down to £26.10 if go on thyroid uk for code
thyroiduk.org/getting-a-dia...
monitormyhealth.org.uk/thyr...
If TPO or TG thyroid antibodies are high this is usually due to Hashimoto’s (commonly known in UK as autoimmune thyroid disease).
About 90% of all primary hypothyroidism in Uk is due to Hashimoto’s. Low vitamin levels are particularly common with Hashimoto’s. Gluten intolerance is often a hidden issue to.
Link about thyroid blood tests
thyroiduk.org/getting-a-dia...
Link about Hashimoto’s
thyroiduk.org/hypothyroid-b...
List of hypothyroid symptoms
thyroiduk.org/signs-symptom...
Thanks so much for all this information.
I forgot to add I had the TPO and TH ab test back in August as part of my fertility screen but they came back <9 sand <10 respectively.
Though my aunt mentioned today that if it’s coupled with an auto immune disease the antibodies might no longer exist.
(This happened to her with her condition - during her diagnosis they were there and after some time they were no longer in her system - they were essentially destroyed)
Thyroid diagnosis seems to be so complex!
Yes 20% of Hashimoto’s patients never have high thyroid antibodies
Ultrasound scan of thyroid can be helpful
sonoworld.co.uk/women-scans...
Before TTC levels need to be stable verywellhealth.com/infertil...
Pregnancy guidelines
thyroiduk.org/having-a-baby-2/
gp-update.co.uk/files/docs/...
IMPORTANT See pages 7&8
Thanks so much for all your replies. It’s so helpful knowing what to ask for on Monday when I speak to my doctor. I will definitely get all the tests as recommended requested.
I spoke to my mom and aunt today and got some interesting information.
All the women in my family have under active thyroids.
My mom has pernicious anaemia on top of it and my aunt has auto immune diabetes.
What I didn’t know was my grandfather also had a pituitary tumor which was medicated for 30 years or so of his life.
I’m wondering based on this is there any further testing or genetic testing I can do to rule out/detect any of these?
Reread all these replies carefully to understand that being left on too small a dose is completely inadequate
TSH suppressed - Doctor wanted to lower my dose of T4
What makes T4 lower? 
Very low TSH and low T4
Concerned about TSH & T4 levels
TSH during pregnancy and right level of T4 and T3
