Lugols is good, you can take as little as a drop which is 3.5mg. You don't want to stir up detox symptoms if you're pregnant, but you want to give your baby all the thyroid support you can. Your baby will take from you and if you are deficient, it will deplete you and your baby won't be getting what it needs and set him/her up for thyroid issues too.
http://www.naturalthyroidchoices.com
is a site that is owned by a woman who was diagnosed with thyroid cancer while pregnant. She underwent a total thyroidectomy and radiation (more than once) and still had cancer markers. She found Dr. David Brownstein (Arthur of "Iodine, Why you need it, Why you can't live without it" and "Salt your way to Health) and he helped her regain her health with desiccated thyroid, Iodine and nutritional supplements. Her children are hypothyroid and take desiccated thyroid and iodine. She runs an Iodine group on yahoo you should join. She and the moderators will be able to answer a lot of your questions.