Basal endocrine Women’s basal endocrine hormone levels are best checked on the 2nd to 5th day of menstruation, with the best time being the 3rd day of menstruation. If the menstrual cycle is shorter than 25 days, it is recommended to check on the 2nd day of menstruation, and if the cycle is longer than 35 days, it can be checked on the 3rd-5th day of menstruation. This period is the early follicular phase and can reflect the functional status of the ovaries, but it cannot predict whether ovulation will occur in the current cycle. Generally, three sex hormone tests are needed: folliculogenic hormone (FSH), luteinizing hormone (LH), and estradiol (E2). The basal values of FSH and LH are 5-10 IU/L. In a normal menstrual cycle, FSH and LH are maintained at low levels in the early follicular phase (day 2 to 3 of menstruation), and monitoring the levels of FSH and LH in the early follicular phase can initially determine the function of the female gonadal axis. 1, Ovarian failure: Basal FSH 40IU/L and elevated LH or 40IU/L is ovarian failure; if it occurs before the age of 40, it is called premature ovarian failure (POF). 2, poor ovarian reserve function (DOR): basal FSH/LH 2 to 3, 6 suggest poor ovarian reserve function (FSH can be in the normal range), or basal FSH >12, which is an early manifestation of poor ovarian reserve function. 3. Basal FSH and LH both 5 IU/L: suggest hypothalamic or pituitary hypofunction, and the distinction between the two needs to be made with the help of gonadotropin-releasing hormone (GnRH) test. 4. If LH/FSH>2 to 3: helps to diagnose polycystic ovary syndrome. Estradiol (E2) levels reflect follicular growth status and are at a low level <50pg/mL early in the normal menstrual cycle. If basal E2 is >60-80pg/mL, it suggests decreased ovarian reserve function. Pre-ovulatory hormones Pre-ovulatory hormone measurements are indicators of whether the follicles are mature, whether ovulation will occur, and whether the endometrium is developing synchronously. They are usually checked when the follicles develop >16mm in diameter, with E2, LH and P. Estradiol (E2) reaches its first peak before ovulation, with each mature follicle secreting 250-300 pg/mL of E2, which decreases rapidly after ovulation. Checking estradiol levels during ovulation can be one of the indicators to monitor follicle development and maturation. If the E2 value is low and does not match the follicle diameter, it suggests the possibility of poor egg quality. lH rises rapidly before ovulation to form a peak, which can be as high as 3-8 times the basal value. lH rapidly returns to follicular phase levels after ovulation. lH peak can be estimated about 36 hours after ovulation. Under normal conditions, blood P during the follicular phase is always at a low level, averaging 0,6-1,9 ng/mL; P secretion begins to increase before ovulation, and after ovulation the ovarian corpus luteum produces a large amount of P. Blood P concentration rises rapidly, generally reaching a maximum level of about 10-15 ng/ml in the mid-luteal phase. Hormones in the mid-luteal phase Elevated progesterone P is the gold standard for evidence of ovulation. The best time to measure it is one week after ovulation is monitored by ultrasound or 6-7 days after basal body temperature rises. At this time, progesterone is theoretically at its highest level in the luteal phase. A blood progesterone level >15ng/mL indicates ovulation and good luteal function; <3ng/L is definitely not ovulating. If the blood progesterone level is <30ng/mL at 6, 8 and 10 days after ovulation or 5-10ng/mL at 7 days after ovulation, it indicates insufficient luteal function. If ultrasound does not indicate ovulation, but progesterone is at 3-5ng/mL, it suggests possible luteinization of unruptured follicles. e2 reaches a second peak in mid-luteal phase, usually about half of the level at the first peak, about 125-200 pg/mL. low e2 levels a week after ovulation also suggest luteal insufficiency. Testosterone (T) and Prolactin (PRL) T is mildly to moderately elevated in patients with PCOS; T levels are significantly elevated in patients with ovarian or adrenal tumors and adrenocortical hyperplasia. It is important to note that serum total testosterone is generally tested, while it is serum free testosterone that is truly active, so some patients with elevated T will also need to be tested for serum sex hormone free protein, dehydroepiandrosterone sulfate, 17alfa hydroxyprogesterone, and cortisol. PRL and has small fluctuations with the menstrual cycle. The secretion of prolactin is unstable, and its secretion state can be affected by emotion, exercise, sexual intercourse, hunger and eating, and has a sleep-related rhythm; PRL secretion increases in the short term after sleep, and rises in the afternoon compared to the morning. Therefore, according to this rhythmical secretion characteristic, blood should be drawn in a calm state on an empty stomach at 9-10 a.m. If PRL is significantly elevated, >100ng/mL can be determined in one test; if PRL is mildly elevated, a second test should be performed; PRL ≥25ng/ml or higher than the normal value of this unit test is considered hyperprolactinemia.