The six sex hormones include FSH follicle stimulating hormone, LH luteinizing hormone, E2 estradiol, P progesterone, T testosterone, and PRL prolactin. Blood is usually drawn on the 2nd-4th day of menstruation, when hormone levels are most stable. Some patients who have not had a period for a long time and also want to have their hormone levels tested can also be checked at this time. The reference range depends on the luteal phase, and if the blood is drawn on the 2nd-4th day of menstruation, the reference value depends on the follicular phase. If the serum FSH value exceeds 10 IU/L and the patient is in the transitional phase of menopause before the age of 40, it indicates a decline in ovarian reserve function. If the patient has amenorrhea, FSH is greater than 40 IU/L and estradiol is less than 10-20 pg/ml, it indicates premature ovarian failure. In patients with polycystic ovary syndrome, high luteinizing hormone and androgen, if the lactogen level is high and the patient is not lactating or pregnant, a pituitary MRI should be done to rule out pituitary tumor.