Dydrogesterone in the Treatment of Endometrial Polyps

Inclusion Criteria: 1. women of childbearing age from 20 to 50 years old 2. with or without menstrual changes: 1. menostaxis (longer than 7 days) 2. shortened menstrual cycles(less than 23 days) 3. menorrhagia(more than twice as much as usual) 4. abnormal vaginal bleeding(non-menstrual vaginal bleeding) 3. with following signs of vaginal ultrasound in the follicular phase (day 1 to day 10 of a menstrual cycle): 1. typical signs with a suspect of EP: (median/high) echo with a regular contour within the uterine lumen; 2. atypical signs with a suspect of EP: punctate cystic areas within the endometrium and the endometrial thickness \>1cm; Exclusion Criteria: 1. no menses within half a year; 2. surgery or drug treatment of endometrial lesions in the past half year; 3. with current intrauterine device; 4. combined with other acute gynecological inflammation; 5. with clinically suspected malignant tumors; 6. long-term use of oral contraceptives; 7. with abnormal liver and kidney function; 8. with benign or malignant breast tumors; 9. with any systemic malignant tumor or a history of tumors; 10. participants who are pregnant.