No sex hormone drugs (including progesterone and estrogen) should be used for at least one month and preferably three months before checking basal sex hormones, otherwise the results are not reliable (except for the need to recheck sex hormones after treatment). To diagnose and treat menstrual irregularities and infertility, we must understand the basal sex hormone level. First of all, we should choose the 2nd to 5th day of menstruation (follicular phase) to check the level of the hormone called basal sex hormone, which is best measured on the 3rd day on an empty stomach. In cases of scanty menstruation and amenorrhea, a negative urine pregnancy test, absence of ≥10mm follicles in both ovaries on vaginal ultrasound, and endometrial thickness of 5mm can also be done as basal status. The unit of examination may vary from hospital to hospital and the range of normal values may also vary. The specific diagnosis should also be judged by the doctor in the hospital where the test is performed: 1. Folliculogenic hormone (FSH) Promotes follicular development and maturation in the ovaries. The optimal value is 5-10 IU/L during the follicular phase. Low FSH value: during estrogen and progesterone treatment, Silhan syndrome, etc. High FSH value: premature ovarian failure, ovarian insensitivity syndrome, primary amenorrhea, etc. Basal FSH level increases with age and its increase is related to the decrease of ovarian reserve capacity. 2. Luteinizing hormone (LH) Promotes ovulation (under the synergistic effect of FSH), formation of corpus luteum and secretion of progesterone. The optimal value is 5-10 IU/L during the follicular phase. Low LH: indicates gonadotropin insufficiency and Silhan syndrome; high LH plus high FSH: indicates ovarian failure. LH/FSH ≥3 is one of the bases for the diagnosis of polycystic ovary syndrome. 3, Estradiol (E2) Mainly to transform the endometrium into a proliferative phase and to promote the development of female secondary sex characteristics. optimal value of E2 is 25-45pg/ml low E2: indicates low ovarian function, premature ovarian failure, and Silhan’s syndrome. 4. Progesterone (P) mainly promotes the endometrium to change from proliferative phase to secretory phase. The follicular phase is usually <1ng/ml. Low P in the late ovulatory phase: it is seen in luteal insufficiency and ovulatory dysfunctional uterine bleeding. 5.Testosterone (T) mainly promotes the development of clitoris, labia and mons pubis. It has an antagonistic effect on estrogen and has some influence on systemic metabolism. High T: Hypertestosteronemia, which can cause infertility. The blood T value is also increased when suffering from polycystic ovary syndrome. 6. Prolactin (PRL) It mainly promotes the proliferation of mammary glands, milk production and lactation. High PRL: prolactinemia, which inhibits the secretion of FSH and LH, suppresses ovarian function and inhibits ovulation.