Blood clots after abortion are mostly caused by excessive menstruation, and a few are caused by shedding of the uterine lining. 1. Excessive menstruation: When you have your period after an abortion, due to the accumulation of too much menstrual blood, which can not be discharged in time, blood clots are sometimes formed, most of them are physiological phenomena, and usually return to normal after two or three times of menstruation. 2. Shedding of endometrium: When you have your first menstrual period after abortion, the menstrual blood may be mixed with some shed endometrial tissues, which are wrapped by the menstrual blood and are often regarded as blood clots. In addition, women need to pay attention to rest after abortion, avoid sexual life, if abnormal menstruation after abortion should also go to the hospital in a timely manner for specialized examination, under the guidance of the doctor treatment.