(1) Diagnosis of precocious puberty in females: E2 is one of the hormonal indicators to determine puberty initiation and to diagnose precocious puberty. precocious puberty is diagnosed with the development of secondary sexual characteristics before the age of 8 years and elevated blood E2 > 275 pmol/L (75 pg/ml). (2) E1/E2 > 1 suggests increased peripheral conversion of E1 and is indirect evidence of increased testosterone (T), as in postmenopause and PCOS. (3) Excessive E2 levels are seen in granulosa cell tumors, ovarian plasmacytic cystadenoma, cirrhosis, systemic lupus erythematosus, obesity, smokers, normal pregnancies and pregnant women with diabetes mellitus. (4) Premature ovarian failure occult stage: elevated basal E2 and normal FSH is the intermediate stage between ovarian failure and normal ovarian function, i.e., premature ovarian failure occult stage. With age and ovarian failure, high FSH and LH and low E2 status will appear. (5) Ovarian failure: lower basal E2 and higher FSH and LH, especially when FSH ≥ 40 IU/L, suggest ovarian failure. (6) Basal E2, FSH and LH are all low, which is hypogonadotropic (Gn) deficiency, suggesting that the lesion is in the hypothalamus-pituitary gland, such as Sheen syndrome. (7) Polycystic ovary syndrome: maintenance of high levels of estrogen without cyclic changes is an endocrine feature of polycystic ovary syndrome (PCOS), which includes elevated levels of E2 and E1, increased secretion of T and LH, decreased secretion of FSH, and LH/FSH > 2 to 3. (8) E is mainly produced by the corpus luteum in early gestation, and after 10 weeks of gestation there is mainly synthesis of fetal-placental units. By the end of pregnancy, E2 is 100 times higher than that of non-pregnant women. e2 can be used as an observational indicator for fertility preservation treatment in patients with miscarriage. (9) Predicting the effect of superovulation (COH) and pregnancy rate ①The pregnancy rate was significantly higher in those with basal E2 <165.2 pmol/L (45 pg/ml) than in those with E2 ≥165.2 pmol/L. (2) Basal E2 > 293.6 pmol/L (80 pg/ml) indicates rapid follicular development and decreased ovarian reserve function regardless of age and FSH; in IVF cycles if basal E2 > 367 pmol/L (100 pg/ml), COH is ineffective, cycle cancellation rate due to low or no ovarian response increases significantly, and clinical pregnancy rate decreases. (10) Indicators for monitoring follicle maturation and ovarian hyperstimulation syndrome (OHSS) ①When follicles ≥ 18 mm and blood E2 ≥ 1100 pmol/L (300 pg/ml) are treated with ovulation promotion, HMG is discontinued and 10 000 IU of HCG is administered intramuscularly. ②E2 < 3670 pmol/L (1000 pg/ml) at the time of follicle maturation with ovulation promotion therapy is generally not OHSS will not occur. ③ When there are more follicles developing at the time of ovulation promotion treatment, E2 >9175pmol/L (2500pg/ml) to 11010pmol/L (3000pg/ml) is a high risk factor for OHSS. ④ When E2 >14 680pmol/L (4000pg/ml) to 22 020pmol/L (6000pg/ml) at the time of superovulation promotion, OHSS will occur. 6000 pg/ml), the incidence of OHSS is nearly 100% and can rapidly progress to severe OHSS. (ii) Progesterone P is secreted by the ovaries, placenta and adrenal cortex, and is mainly derived from the placenta during pregnancy. P in the peripheral blood during the menstrual cycle mainly comes from the corpus luteum formed after ovulation, and its level gradually increases with the development of the corpus luteum. During the follicular phase, P is always at a low level, averaging 0.6-1.9 nmol/L, generally <3.18 nmol/L (1ng/ml); when the LH peak occurs before ovulation, granulosa cells of mature follicles luteinize under the action of LH ovulation peak and secrete a small amount of P. Blood P concentration can reach 6.36 nmol/L (2ng/ml), and the initial rise of P is an important indication of imminent ovulation The initial rise in P is an important indication of imminent ovulation. After ovulation, the corpus luteum forms and produces a rapid rise in P concentration; when the corpus luteum matures (6-8 days after the LH peak), blood P concentration reaches a peak of 47.7-102.4 nmol/L (15-32.2 ng/ml) or higher. If the corpus luteum begins to atrophy 9-11 days after ovulation without pregnancy, the P secretion concentration decreases abruptly and drops to follicular phase level 4 days before menstruation. The blood P level changes parabolically throughout the luteal phase. Progesterone test value coefficient conversion: ng/ml?3.18=nmol/L Clinical significance of P measurement: 1. Normal basal value P value should be maintained at <1ng/ml throughout the follicular phase, 0.9ng/ml is the minimum for endometrial secretory phase changes. p value starts to rise with the appearance of LH peak and increases substantially after ovulation. 2. Early follicular P > 1ng/ml predicts poor ovulation promotion efficacy. 3.Determination of ovulation Mid-luteal P>16nmol/L (5ng/ml) indicates ovulation in this cycle (except LUFS); <16nmol/L (5ng/ml) indicates no ovulation in this cycle. 4.Diagnosis of luteal insufficiency (LPD) A mid-luteal P <32nmol/L (10ng/ml), or a total of 3 measurements of P <95.4nmol/L (30ng/ml) on the 6th, 8th and 10th day after ovulation is considered LPD; conversely, luteal function is normal. 5, luteal atrophy is not complete P is still higher than the physiological level on 4-5 days of menstruation, suggesting luteal atrophy is not complete. 6.Judging the prognosis of in vitro fertilization-embryo transfer (IVF-ET) (1) P≥3.18nmol/L (1.0ng/ml) on the day of myocardial HCG injection should be regarded as elevated, which can lead to decreased endometrial tolerance, embryo implantation rate and clinical pregnancy rate. p>4.77nmol/L (1.5ng/ml) has the possibility of premature luteinization. (2) In IVF-ET long protocol ovulation promotion, even if there is no increase in LH concentration on the day of intramuscular HCG injection, if P(ng/ml)?1000/E2(pg/ml) >1, it suggests possible premature follicular luteinization or ovarian malfunction, and the clinical pregnancy rate is significantly reduced. 7. Pregnancy monitoring (1) Changes in P during pregnancy: P is produced by the ovarian corpus luteum in early pregnancy, and placental syncytial trophoblasts are the main source of P production from 8 to 10 weeks of gestation onwards. As pregnancy progresses, the P value in maternal blood gradually increases, with blood P values of 79.5 to 89.2 nmol/L (25 to 28.6 ng/ml) at 7 to 8 weeks of gestation, 120 nmol/L (38 ng/ml) at 9 to 12 weeks of gestation, 144.7 nmol/L (45.5 ng/ml) at 13 to 16 weeks of gestation, and 346 nmol/L at 21 to 24 weeks of gestation. P is an important observational indicator for the treatment of miscarriage patients. (2) Application of P in monitoring embryonic development: Measurement of serum P concentration in early pregnancy to evaluate luteal function and monitor the therapeutic effect of exogenous P can significantly improve pregnancy prognosis. Early pregnancy P levels in the range of 79.25-92.76 nmol/L (25-30 ng/ml) suggest intrauterine pregnancy survival with a sensitivity of 97.5% and a slow increase in progesterone levels with the growth of the gestational week. Decreased P concentration in early pregnancy suggests luteal insufficiency or abnormal embryonic development, or both, but 10% of normal pregnant women have serum progesterone values below 79.25 nmol/L. P <47.7 nmol/L (15 ng/ml) in pregnancy suggests intrauterine gestational dysplasia or ectopic pregnancy. P levels below 15.85nmol/L (5ng/ml) during pregnancy suggest a dead pregnancy, either intrauterine or ectopic. 8. Identification of ectopic pregnancy Ectopic pregnancy has low blood P levels, with P < 47.7 nmol/L (15ng/ml) in most patients and ≥ 79.5 nmol/L (25ng/ml) in only 1.5% of patients. Blood P levels can be used as a reference in the differential diagnosis between intrauterine and ectopic pregnancy. 90% of normal intrauterine pregnancies have progesterone > 79.5 nmol/L and 10% < 47.6 nmol/L.