TSH level evaluation at least every 12 months. If left untreated, physical and mental abnormalities, fetal anomalies including physical and mental defects, hyperlipidemia, coronary artery disease, and a life-threatening complication of untreated hypothyroidism called myxedema coma, associated with sever hypothermia, bradycardia, seizures, and decreased cardiac output eventually resulting in a coma can