I found out while I wasnt pregnant. They didnt find it with blood tests, so I had to get an ultrasound. Do you know if anyone in your family has a thyroid disease? I inherited mine from my mother but she had the opposite, she had hyper, where she lost alot of weight. My advice to you, if you do have a thyroid problem, eat real healthy during ur pregnancy, dont go overboard with junk cuz if it turns out to be hypo, you could have a hard time losing the weight after the baby.