Early pregnancy: Levothyroxine prescribed with levels normal

[Raspberry534]

I (F 39) am pregnant (3 wks, 5 days) and today I was prescribed 12.5 micro grams of Levothyroxine by my new endocrinologist. My blood results of TSH, fT3 and fT4 are normal:

TSH: 2.78 [Ref range 0.27 - 4.2]

fT3: 4.06 [Ref range 3.1 - 6.8]

fT4: 14.92 [Ref range 12 - 22]

The endocrinologist told me the medication is not for me but 'for the baby'. I don't have a history of hypothyroidism, I did have 2 thyroid nodules (under 1 cm) earlier this year but they both have disappeared by now.

During the appointment, I mentioned I have problems swallowing (due to my multiple sclerosis) and that I have been fatigued.

Not sure, if it's related to the prenatal supplement but while taking prenatal iodine early this year, my TSH level rose over the limit (5.1 mIU/L [Ref range 0.27-4.2]) a couple of times. Thankfully it came back two-three months later after discontinuing. This particular endocrinologist wasn't however aware of my TSH fluctuation.

I'd like to ask if it's a normal practice to prescribe Levothyroxine in pregnancy and what the reasons could be behind my prescription.

Thank you very much for any ideas and comments!

[gimel]

It is very important for the welfare of the baby that you have adequate thyroid hormone levels during preegnancy.   there is a lot of info about this on the internet.  

It is good that the doctor recognized a potential problem with your thyroid levels.  Even though all are in "normal' ranges, that does not mean they are optimal.  First, TSH is useful for diagnosis of only overt primary hypothyroidism.  All other hypothyroid conditions are best diagnosed by an evaluation of symptoms typical of hypothyroidism as well as the actual thyroid hormones, Free T4 and Free T3.  Your TSH is in range, so it is nohelp in further diagnosis.  Your FT4 is only at 29.2 % of its range, and your FT3 is only at 25.9 % of its range.  So we need to know what symptoms you have.  

Please before further discussion, pleases review the following list from the Mayo Clinic and tell us which you symptoms seem to have.  

Tiredness.
More sensitivity to cold.
Constipation.  (need to use laxatives or fiber)
Dry skin.  (need to use skin creme)
Weight gain. or difficulty losing weight.
Puffy face.
Hoarse voice.
Coarse hair and skin.
Muscle weakness.
Muscle aches, tenderness and stiffness.
Menstrual cycles that are heavier than usual or irregular.
Thinning hair.
Slowed heart rate,
Depression.
Memory problems.