Hi, Thanks for the query. Some thyroid abnormalities occur during pregnancy due to hormonal changes as a result of pregnancy itself and these are normal. The TSH is actually expected to increase during pregnancy. I am not aware of the reference levels of TSH for the lab where you got the report [they are usually mentioned along with the report] but the level suggests that the TSH is low. This indicates that you may be having excess thyroid hormones or hyperthyroidism in medical terms. The second test is advisable to ensure that the results of the first test were not by chance. Thyroid abnormalities are common and may occur at any point in life so there is no need to worry. You must get your thyroid examined by a surgeon preferably as well as an ultrasound of the thyroid if the results of the second test also suggest decreased TSH. Other tests like free t3 and t4 will be needed along with tests to know the cause like graves disease. In any case drugs like propylthiouracil are used to control thyroid. They do not cause much harm to the baby. Only the lowest doses need to be used. Please do not worry as these are common issues. Think about your wonderful baby and be happy. Just take any treatment that may be needed for the thyroid according to the report and you will be fine. Thanks for using HCM, feel free to post any other queries and I would be glad to help. Dr Madhuri Bagde