Thyroid problems are a very big deal even if you're NOT pregnant. They can cause so many problems both short and long term even just for you, let alone anything it could do to your baby. If properly treated you and your baby can be very healthy and do just fine, so it's nothing to be *scared* of, just not something that would be in the best interest of you or your baby for you to downplay.
You are very fortunate to have a doctor who even considered diagnosing you! There are tons of us out there who have had to struggle and beg for *years* to get diagnosed with thyroid problems (It took me 12 years and 13 doctors before I found one to confirm what I've known since I was 15).
Your doctor needs to do a complete thyroid panel. Most just do TSH and T4, which tells so little of the story it's basically useless. One of the most important things is testing you for antibodies. If you have antibodies your TSH can swing back and forth minute to minute even, going from severely hyper to severely hypo. Just because you got a normal TSH at that exact moment of the blood draw means nothing about your overall thyroid function until you know whether or not you have antibodies.
According to this article: http://findarticles.com/p/articles/m...31/ai_75176512
"Elevated thyroid-stimulating immunoglobulin (TSI) can cause fetal hyperthyroidism. TSI crosses the placenta less than 5% of the time at 15 weeks but nearly 100% of the time at 30 weeks."
"Women with Hashimoto's disease also should be screened for TSI in the third trimester because about 5% of women with this condition have TSI."
Also there are a lot of flaws with the TSH lab ranges. Most doctors and labs don't even know about the new updated ranges. TSH should be from 0.3-3.0. Most people feel best in the lower ranges, and if you're on Armour it will suppress your TSH. TSH is a pituitary hormone that shows how much thyroid hormone your body is ASKING for, not how much it has, so if you're on a replacement dose that gives your body all it needs, it doesn't ask for more, so your TSH will be way lower. There has also been talk of lowering the lab ranges even further to 2.5 or even 2.0. http://www.mercola.com/2001/jan/28/thyroid_disease.htm http://thyroid.about.com/cs/testsfor...a/labs2003.htm
Synthroid is not at all side-effect free or even safe for most non-pregnant people...but natural thyroid (Armour) IS! Armour exactly mimics what your body produces and the *only* "side effects" are if you have too much, or too little. Google Synthroid miscarriage or whatever the brand name of your synthetic medication is, and then Armour miscarriage. The health and safety of my children is the #1 reason that convinced me to switch to Armour even though that was a tough decision for me since I was vegetarian.
Please, please for the sake of your baby and your own health, check out the sites Bigeyes mentioned. There is a wealth of information and people who know so much and are eager to help you. You may have symptoms you don't even recognize are related, or even if you're asymptomatic it could be causing underlying problems for you and your baby.