One patient had been treated as having PCOS because she had irregular periods and her ovaries had polycystic-like changes on ultrasound. When the pregnancy turned out to be inevitably miscarried, it was discovered that the real cause was hypothyroidism. With this case I would like to talk about polycystic ovary syndrome (PCOS) and polycystic change of ovaries (PCO) Polycystic ovary syndrome (PCOS) and polycystic-like change of ovaries (PCO) are two different concepts. The authoritative book on gynecology, “Chinese Obstetrics and Gynecology”, states: “PCO is only a morphological sign, any disease that causes excessive androgen secretion in the body, such as cortisolism, hyperprolactinemia, adrenal or ovarian androgen-secreting tumors, etc. can cause; other causes of persistent anovulation, abnormal thyroid function, etc. can also cause PCO; these conditions are not PCOS. In addition, about 20% of normal women without clinical symptoms have PCO signs during ultrasound examination. PCOS refers to a series of manifestations such as menstrual disorders, persistent ovulation disorders, hyperandrogenemia, and ovarian polycystic changes caused by excessive androgen production due to benign proliferation of ovarian vesicular cells with onset around puberty.” Therefore, when your ovaries have polycystic-like changes during ultrasound examination, do not easily diagnose polycystic ovary syndrome (PCOS), but make sure to find out the cause and properly diagnose and treat it. 2 about PCOS in adolescence Most adolescents have irregular menstruation or sporadic ovulation, and most adolescents will have transient androgen elevation. The cause of menstrual disorders as well as Kaohsiung symptoms may be due to the HPO axis being in an overdeveloped and mature stage, or it may be due to PCOS. Therefore, PCOS should not be overdiagnosed during adolescence, but menstrual disorders and Kaohsiung symptoms should be treated aggressively.