The value of estradiol at the time of menstruation is 99.1-447.7 pmol/L. Because the hormone level decreases at the time of menstruation, estradiol will have a lower value than at other times of the year. The blood test should be done on an empty stomach if possible, and also on the 2nd-5th day of menstruation, within 9-11pm, to increase the accuracy. As long as the result is within the range, it is normal. However, when estradiol is high, it can cause hyperplasia of the endometrium, resulting in the development of polyps, fibroids, and even submucosal fibroids. It is necessary to antagonize estrogen by taking oral progestin in the second half of the cycle to avoid the manifestation and occurrence of gynecological diseases.