This study is intended to observe the therapeutic effect of dydrogesterone on endometrial polyps and provide a reference for clinical treatment.

Endometrial polyps are a common female endometrial lesion.The long-term unrestrained exposure of estrogen to local tissue is one of the causes of polyp formation.Studies suggested that the progesterone can accelerate the regression rate of endometrial polyps due to its antiestrogenic effects.Based on this, investigators intended to observe the therapeutic effect of dydrogesterone on endometrial polyps and provide a reference for clinical treatment.

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.