[Isthmic pregnancy located in a previous caesarean section scar treated with methotrexate. A case report].

We report a case of a patient who presented an isthmic pregnancy successfully treated with an intramuscular injection of methotrexate. The diagnosis of isthmic pregnancy was made clinically (cervical colour was normal, inferior segment soft and enlarged) and echographically (long cervix, foetal sack situated in the isthmus and the uterine body was empty). An isthmic full term pregnancy is possible but would carry major haemorrhagic risk. There are several therapeutic options if the pregnancy is interrupted: medical treatment of methotrexate, curettage, curettage with embolisation of the uterine arteries and as a last resort, hysterectomy. The success of conservative treatment seems to be related to the criteria known for the cervical pregnancy, which are cardiac activity, the level of HCG, gestational age and cranial-caudal length.