The intermittent menstruation for a month is a manifestation of menstrual disorders, which can be seen with ovarian endocrine dysfunction and also with organic diseases of the uterus. 1. uterine fibroids: uterine fibroids are the main cause of abnormal bleeding in the uterine cavity, resulting in incomplete menstrual dripping. It is usually seen in submucosal fibroids, or larger, multiple subplasmic, interstitial fibroids; 2. Intrauterine placement of the birth control ring: the birth control ring is a foreign body to the uterine cavity after the placement of the birth control ring, which can stimulate a sterile inflammatory reaction in the endometrium. If this reaction cannot be adapted, it will cause irregular bleeding, manifested as prolonged menstrual periods, incomplete menstrual dripping or increased menstrual blood; 3, abnormal ovarian function, insufficient level of progesterone secretion or incomplete luteal atrophy, so that the progesterone level cannot drop rapidly, which leads to irregular endometrial exfoliation and prolonged menstrual periods.