Pink color in the leukorrhea indicates vaginal bleeding, and the common causes of vaginal bleeding are as follows: I. Inflammation, such as vaginitis, endometritis, cervicitis, cervical polyps and so on. Second, pregnancy-related, including miscarriage, ectopic pregnancy, abortion, partial retention of placenta after delivery. Cervical lesions, such as low-grade squamous intraepithelial neoplasia, high grade squamous intraepithelial neoplasia, cervical cancer and so on. Ovarian endocrine dysfunction, mainly including anovulatory dysfunctional uterine bleeding and ovulatory menstrual disorders. Fifth, others include, injury, foreign body, exogenous estrogen, such as oral hormonal drugs caused by sudden withdrawal, can also cause abnormal vaginal bleeding.