Final answer:
A cause of recurrent abortion can be scar tissue within the uterine tube following a sexually transmitted bacterial infection. In some cases, the scar tissue blocks the tube completely, while in others it impedes the progress of the embryo into the uterus. Treatment options depend on the timing and severity of the tubal pregnancy.
Step-by-step explanation:
A cause of recurrent abortion can be the presence of scar tissue within the uterine tube following a sexually transmitted bacterial infection. This scar tissue can block the tube completely or impede the progress of the embryo into the uterus, resulting in a tubal pregnancy. Approximately half of tubal pregnancies resolve spontaneously, but in the remaining cases, medical or surgical intervention is necessary. Early detection allows for the use of methotrexate to arrest the development of the embryo, while late diagnosis may require surgical repair of the ruptured uterine tube.