Abdominal pain 20 days after the abortion is most likely to be a reproductive tract infection, there may also be the abortion did not do a clean existence of intrauterine residue. Abortion is a means of terminating an early pregnancy, which is a process of using negative pressure suction to clean out the gestational sac as well as the meconium from the uterine cavity. Just after the abortion surgery need to discharge the blood in the uterine cavity, which is the mouth of the uterus is open, the uterus and the outside world, easy to reproductive tract infections, coupled with abortion is a uterine operation of a kind of surgical procedure, more increase the chances of infection, so the abortion surgery must be oral antibiotics to prevent infection. The main symptoms of reproductive tract infection after abortion are lower abdominal pain, vaginal bleeding or accompanied by fever. If the abortion is incomplete, there will also be lower abdominal pain, vaginal bleeding, then you can go to the hospital to check, do gynecological ultrasound, blood tests to determine what causes lower abdominal pain, according to the results of the examination can be treated.