Help me understand

[nettiboo1982]

I had my blood tested at hospital last week too ensure I'm on correct dose of thyroxine during pregnancy my results were t4 11.5 and tsh was 0.65 so now I'm told I'm possibly on too much levo help I don't understand

[diogenes Remembering]

Your FT4 is exactly where I would expect it for mid to late pregnancy as is your TSH. It's absolutely essential to have sufficient T4 for your baby's health. Indeed it's now recommended that when pregnant you should take more T4 than when not. TSH between about 0.6-1 is ideal.

[Clutter]

Nettiboo,

Whoever has told you you are overmedicated is wrong. NICE recommend the TSH of pregnant women should be in the low-normal range of 0.4-2.0 with FT4 in the upper range. You haven't included FT4 range but 11.5 is usually low in range.

__________________________________________________________________________________________

I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.

[nonstopmummy in reply to Clutter]

Hi Clutter, do you perchance have a link to these NICE guidelines about pregnancy ft4 being in upper quartile etc? Want to show to my (idiot) endo, who is actually advising my GP to lower my levo even though my ft4 is only at 35% in the range. I am going to up the doseage myself with or without his help but I dread to think of the number of miscarriages he has undoubtedly caused to the poor women who listened to him. Ta x

[Clutter in reply to nonstopmummy]

Nonstopmummy,

I can't supply a link because the NICE CKS Summary was revised in April 2016 but I have copied and pasted the information from the pre April 2016 CKS below and highlighted the bit about FT4.

Preconception or pregnant

Scenario: Subclinical or overt hypothyroidism in the prenatal or antenatal period

Age from 16 years onwards (Female)

Pre-existing subclinical hypothyroidism

How should I manage a woman with pre-existing subclinical hypothyroidism who is pregnant or planning a pregnancy?

Check thyroid function tests before conception if they have not been done in the past 6 months.

Advise women planning a pregnancy to consult their GP as soon as they think they may be pregnant.

For women with known subclinical hypothyroidism who are already receiving levothyroxine treatment (perhaps because their thyroid-stimulating hormone [TSH] concentration was greater than 10 mU/L):

At confirmation of pregnancy, immediately increase the levothyroxine dose, and perform thyroid function tests while awaiting referral to a specialist:

The dose should be increased usually by adding at least 25–50 micrograms levothyroxine; the size of the initial increase in dose will depend on the dose the woman is already taking and the TSH and free thyroxine (FT4) concentrations.

Aim for a TSH concentration in the low-normal range (0.4 mU/L to 2.0 mU/L) and an FT4 concentration in the upper reference range.

If there is any uncertainty about what dose to prescribe, seek immediate specialist advice so that there is no delay in the woman receiving an adequate dose of levothyroxine.

Monitor TSH and FT4 levels:

Every 4 weeks during titration of levothyroxine.

Every 4 weeks during the first trimester, and again at 16 weeks and at 28 weeks of gestation, in a woman who is on a stable dose of levothyroxine.

More frequent tests may be appropriate on specialist advice.

All women with subclinical hypothyroidism who are pregnant or planning a pregnancy and are not receiving levothyroxine treatment should be started on levothyroxine therapy while waiting for referral to a specialist. Management is the same as for women with a new diagnosis of subclinical hypothyroidism who are pregnant or planning a pregnancy.

Basis for recommendation

These recommendations are based on information from a consensus guideline produced by the Association for Clinical Biochemistry, the British Thyroid Association, and the British Thyroid Foundation [BTA et al, 2006]; expert opinion in a guideline produced by the Endocrine Society [Abalovich et al, 2007]; expert opinion in a learning module [Edwards and Vanderpump, 2007]; and the opinion of CKS expert reviewers. Some of the evidence to support these recommendations is based on observational studies.

In women with hypothyroidism, the need for levothyroxine is increased in pregnancy by 30–50% above the preconception dosage, and absorption of levothyroxine may be diminished, therefore it is important to increase the dose quickly in women already on levothyroxine [BTA et al, 2006; Abalovich et al, 2007; Reid et al, 2010].

There is evidence of increased fetal loss, and psychomotor and IQ deficits, in infants born to mothers with undiagnosed or inadequately treated hypothyroidism (including subclinical hypothyroidism) [Casey et al, 2005].

The increase in the levothyroxine dose is necessary to maintain normal serum thyroid-stimulating hormone (TSH) and free thyroxine (FT4) levels for the gestational age [BTA et al, 2006].

The recommendations on monitoring of thyroid function (TSH and FT4 levels) are based on expert opinion in guidelines [BTA et al, 2006].

New diagnosis of subclinical hypothyroidism

How should I manage a woman with a new diagnosis of subclinical hypothyroidism who is pregnant or planning a pregnancy?

All women with a new diagnosis of subclinical hypothyroidism who are pregnant or planning a pregnancy should be started on levothyroxine therapy while waiting for referral to a specialist.

Follow local specialist advice regarding the dose, as experts recommend different starting doses (varying from 25 micrograms to 100 micrograms to be taken each morning).

Monitor thyroid-stimulating hormone (TSH) and free thyroxine (FT4) levels:

Every 4 weeks during titration of levothyroxine.

Every 4 weeks during the first trimester, and again at 16 weeks and at 28 weeks of gestation, in a woman who is on a stable dose of levothyroxine.

More frequent tests may be appropriate on specialist advice.

Aim for a TSH concentration in the low-normal range (0.4–2.0 mU/L) and an FT4 concentration in the upper reference range.

Basis for recommendation

These recommendations are based on information from a consensus guideline produced by the Association for Clinical Biochemistry, the British Thyroid Association, and the British Thyroid Foundation [BTA et al, 2006]; expert opinion in a guideline produced by the Endocrine Society [Abalovich et al, 2007]; expert opinion in a learning module [Edwards and Vanderpump, 2007]; and the opinion of CKS expert reviewers. Some of the evidence to support these recommendations is based on observational studies.

In women with hypothyroidism, the need for levothyroxine is increased in pregnancy by 30–50% above the preconception dosage, and absorption of levothyroxine may be diminished; therefore, it is important to increase the dose quickly in women already on levothyroxine [BTA et al, 2006; Abalovich et al, 2007; Reid et al, 2010].

There is evidence of increased fetal loss, and psychomotor and IQ deficits, in infants born to mothers with undiagnosed or inadequately treated hypothyroidism (including subclinical hypothyroidism) [Casey et al, 2005].

The increase in the levothyroxine dose is necessary to maintain normal serum thyroid-stimulating hormone (TSH) and free thyroxine (FT4) levels for the gestational age [BTA et al, 2006].

The recommendations on monitoring of thyroid function (TSH and FT4 levels) are based on expert opinion in guidelines [BTA et al, 2006].

Pre-existing overt hypothyroidism

How should I manage a woman with pre-existing overt hypothyroidism who is pregnant or planning a pregnancy?

Check thyroid-stimulating hormone (TSH) and free thyroxine (FT4) levels before conception if possible, to check adequacy of treatment and to make sure the woman is stable and understands the importance of adherence to levothyroxine.

If the woman has a history of Graves' disease, refer her to an endocrinologist for evaluation.

Advise the woman to consult her GP as soon as she thinks she may be pregnant.

At diagnosis of pregnancy, immediately increase the levothyroxine dose and check TSH and FT4 levels while waiting for referral to a specialist:

The dose should be increased usually by adding at least 25–50 micrograms levothyroxine; the size of the initial increase in dose will depend on the dose the woman is already taking and the TSH and FT4 concentrations. A 30–50% increase in dosage may be required. If there is any uncertainty about what dose to prescribe, seek immediate specialist advice so that there is no delay in the woman receiving an adequate dose of levothyroxine.

Check TSH and FT4 levels every 4 weeks until stabilized, aiming for a TSH concentration in the low-normal range (0.4–2.0 mU/L) and an FT4 concentration in the upper reference range.

Monitor TSH and FT4 levels:

Every 4 weeks during titration of levothyroxine.

Every 4 weeks during the first trimester, and again at 16 weeks and at 28 weeks of gestation, in a woman who is on a stable dose of levothyroxine.

More frequent tests may be appropriate on specialist advice.

Basis for recommendation

These recommendations are based on a UK consensus guideline produced by the Association for Clinical Biochemistry, British Thyroid Association, and the British Thyroid Foundation [BTA et al, 2006], and expert opinion in a guideline produced by the Endocrine Society [Abalovich et al, 2007].

In women with hypothyroidism, the need for levothyroxine is increased in pregnancy by 30–50% above the preconception dosage, and absorption of levothyroxine may be diminished; therefore, it is important to increase the dose quickly in women already on levothyroxine [BTA et al, 2006; Abalovich et al, 2007; Reid et al, 2010].

There is evidence of increased fetal loss and IQ and psychomotor deficits in infants born to mothers with undiagnosed or inadequately treated hypothyroidism [Haddow et al, 1999; Pop et al, 1999; Casey et al, 2005].

The increase in the levothyroxine dose is necessary to maintain normal serum TSH and FT4 for the gestational age. A TSH concentration of 0.4 mU/L to 2.0 mU/L is normal for pregnancy [BTA et al, 2006].

Monitoring of thyroid function tests at least once in each trimester aims to detect inadequately treated hypothyroidism, thereby reducing the risk of long-term adverse effects on the psychomotor and auditory systems of the neonate.

The recommendation to refer women with a history of Graves' disease to an endocrinologist for evaluation is based on guidelines developed by the European Thyroid Association [Laurberg et al, 1998]; expert opinion in a clinical practice guideline on the investigation and management of primary thyroid dysfunction produced by the Thyroid Working Group, a multidisciplinary team composed of family physicians, laboratory specialists, and endocrinologists [Alberta Medical Association, 2008]; and expert opinion in a review article [Brent, 2008].

New diagnosis of overt hypothyroidism

How should I manage a woman with a new diagnosis of overt hypothyroidism who is pregnant or planning a pregnancy?

If the woman is planning a pregnancy and is newly diagnosed with overt hypothyroidism:

Start treatment (see prescribing information for information on how to do this), and advise delaying conception until she is stabilized on thyroxine replacement therapy.

Advise her to consult her GP as soon as she thinks she may be pregnant, because her thyroid-stimulating hormone (TSH) levels will need to be checked and her levothyroxine dose increased.

If the woman is pregnant and is newly diagnosed with overt hypothyroidism:

Start treatment with levothyroxine immediately; see prescribing information. There should be no delay in starting treatment.

Refer for further management.

The target TSH concentration in pregnancy is 0.4 mU/L to 2.0 mU/L, depending on trimester-specific normal TSH ranges.

Basis for recommendation

These recommendations are based on a UK consensus guideline produced by the Association for Clinical Biochemistry, the British Thyroid Association, and the British Thyroid Foundation [BTA et al, 2006], and expert opinion in a guideline produced by the Endocrine Society [Abalovich et al, 2007].

The need for levothyroxine is increased in pregnancy in women with hypothyroidism, and absorption of levothyroxine may be diminished. It is therefore important to intervene quickly [BTA et al, 2006].

There is evidence of increased fetal loss and IQ deficits in infants born to mothers with undiagnosed or inadequately treated hypothyroidism [Haddow et al, 1999; Pop et al, 1999; Casey et al, 2005].

The increase in the levothyroxine dose is necessary to maintain normal serum thyroid-stimulating hormone and free thyroxine levels for the gestational age [BTA et al, 2006].

[nonstopmummy in reply to Clutter]

Perfect, thanks Clutter! 😃

[Glynisrose]

How do you feel? Thats the most important thing rather than numbers. Doctors always panic and reduce when your TSH is suppressed but this can happen with any thyroxine replacement. RESIST unless you are habing hyper symptoms.

[nettiboo1982]

sorry for delayed reply my phone was plunged in water after posting so no longer works oops! Thank you for reply I am feeling ill actually keep getting heart flutters and today my arm muscles were contracting at will the only time that has happened before was when a junior doctor started me straight on 125 mcg. I don't know if I'm on too much I'm only 16weeks into pregnancy I'm just scared about what it means if I don't take enough but the flipped too that I'm frightened what taking too much does too baby. Tried ringing docs Today but seemingly busy as usual