Ovulation bleeding refers to breakthrough bleeding in the endometrium due to changes in hormones secreted by the ovaries in the middle of the menstrual cycle. This is a normal physiological phenomenon that usually ends within a day or two.

1. Hormone changes: In the middle of the menstrual cycle, the ovaries secrete a large number of egg cells, and it takes several days for these egg cells to mature. During this process, the ovaries secrete large amounts of estrogen and progesterone, which can cause breakthrough bleeding in the endometrium.

2. Individual differences: Everyone’s physique is different, which may lead to ovulation bleeding. Some women may experience regular bleeding during ovulation, while others may experience light bleeding.

3. Disease factors: Some diseases, such as prolonged menstrual cycle, endometrial diseases, endocrine diseases, etc., may also cause ovulation bleeding.