Pregnant. What should my TSH level be?

[NaomiMay]

Hi if anyone could help,

I have currently found out I'm pregnant and in the 1st trimester.

I'm struggling to find any guidelines on what my TSH should be? I think I remember from last time they should be below 2.0mU/L but Google is coming up 0-2.5mU/L but this isn't official NHS or NICE guidelines.

My TSH level is currently 2.25mU/L, so unsure at the moment if I need to act on this or not?

Any help is greatly appreciated.

[SeasideSusie Remembering]

NaomiMay

This is an old article (2006) from British Thyroid Association so may not be relevant or acceptable now:

british-thyroid-association...

Page 40:

• The thyroid status of hypothyroid patients should be checked with TSH + FT4

during each trimester (II,B). Measurement of T3 is not appropriate.

The FT4 level should be maintained at the upper end of the non-pregnant reference

range in the first trimester, with the TSH at the lower end of the reference range or a

little below (0.4 – 2.0mU/L would be appropriate as this is normal for pregnancy).

Results should ideally be monitored against trimester-related reference range

This is more up to date and from NHS Frimley Health:

frimleyhealthandcare.org.uk...

Page 4:

.1 Hypothyroidism (underactive)

...

Thyroid function tests should be performed three monthly in all women planning pregnancy, aiming to maintain TSH < 2.0 miU/l.

• Women with a history of hypothyroidism should have TFTs performed at booking.

Compliance with thyroid supplementation should be clarified with the woman and

documented in the maternal notes. If the results of TFTs show inadequate replacement despite good compliance (TSH > 2.5 miU/l, free T4 < 10.0 pmol/l, free T3 < 3.5 pmol/l,) the dose of levothyroxine should be increased by 25-50mcg (by 25mcg if on </=125mcg OR 50 mcg if >/=150mcg) daily and response checked with repeat TFTs 4 weeks after any dose change.

• Aim to keep TSH </= 2miU/l. Note TSH can be artificially suppressed by hCG cross-

reactivity, therefore important to check free T4 levels remain adequate

(i.e., free T4 > 12 pmol/l).

....

However, most articles do seem to state <2.5

[NaomiMay in reply to SeasideSusie]

Hi SeasideSusie,

Thank you for sharing this article.

I have done another post which is a bit long winded and complicated 🙈

healthunlocked.com/thyroidu....