There are several possible reasons for having your period twice a month: 1. Ovulatory bleeding. Most people’s second period is actually ovulatory bleeding. It usually manifests itself as sudden vaginal bleeding again about 10 days after the period is over. Usually the second period contains a small amount of curry-colored discharge that lasts for as short as half a day or as long as 3-4 days, and the bleeding usually stops on its own after 3-5 days. During this period, there may be slight ovulation pain and back pain, which can be untreated when it is not obvious. Occasional ovulatory bleeding does not require special treatment, but if you have two periods a month for a long time, you need treatment. 2. Functional uterine bleeding. It is often manifested as irregular menstrual cycle, increased menstrual volume, prolonged periods or irregular vaginal bleeding. 3. Exogenous hormonal stimulation, some women like to take drugs containing hormones, which may lead to imbalance of hormone levels in the body and menstrual disorders. 4. Other gynecological diseases, such as cervical polyps, acute vaginitis, cervical cancer, submucosal fibroids, etc., can cause irregular vaginal bleeding.