It is the bleeding that occurs at the time of ovulation i.e. when ovary releases the egg, which is different from menstrual flow. Women with regular menstrual periods can easily differentiate between them. It can be pink to red in colour and may occur for 1 or 2 days.
The exact cause of bleeding at the time of ovulation is not known. It is attributed to emerging follicles. Hormonal changes influence ovaries to form 20 follicles with immature egg, and it’s out of these that a single follicle matures. This process of maturing and bursting out of ovum from the follicle causes pain or bleeding. Severe or long-lasting bleeding at the time of ovulation can be due to some gynaecological condition like endometriosis, fibroid etc.
The bleeding should subside in two days. Any form of bleeding other than menses for more than 3 days should be investigated. In case of irregular menses one cannot make out ovulation bleeding. Only if ovulation bleeding is associated with pain or severe discomfort or if the bleeding is severe, it might be something to worry about.