Progesterone is an important sex hormone in women, first of all, we should understand the dynamics of progesterone in the body: 1, the basal value is generally <1ng/ml normally, the blood P during the follicular phase has been at a low level, averaging 0.6~1.9nmol/L, generally <10nmol/L (3.15ng/ml); 2, when the LH peak appears before ovulation, the P secretion begins to increase, after ovulation, the corpus luteum produces a large amount of P When the corpus luteum matures (6~8 days after the LH peak), the blood P concentration reaches a peak of 47.7~102.4nmol/L (15~32.2ng/ml) or higher, and then decreases continuously; 4. 5. The P level in peripheral blood changes parabolically throughout the corpus luteum. Progesterone test time and role: 1, determine ovulation: mid-luteal (menstrual cycle of 28 days for women on the 21st day of menstruation) P>16nmol/L (5ng/ml) suggests ovulation, 16nmol/L (5ng/ml) suggests anovulation. 2. Diagnosis of luteal insufficiency (LPD): P32nmol/L (10ng/ml) at mid-luteal phase, or P measured three times on the 5th, 7th and 9th day after ovulation, with a total of 95.4nmol/L (30ng/ml) as LPD; or P47.7nmol/L (15ng/ml) before the 10th week of pregnancy as the criteria for the diagnosis of LPD. 3. Identification of ectopic pregnancy: the blood P level of ectopic pregnancy is low, with most patients having blood P47.7nmol/L (15ng/ml). Only 1.5% of patients have blood P ≥ 79.5 nmol/L (25 ng/ml). Blood P levels can be used as a reference in the differential diagnosis of intrauterine versus ectopic pregnancy in 90% of normal intrauterine pregnancies 79.5 nmol/L and 10% 47.6 nmol/L.