Case: A 34-year-old woman, G5 P2 was seen at the Royal Derby Hospital in early pregnancy. Previous deliveries were by emergency caesarean section, the first at 30 weeks of gestation for a ruptured uterus and the second at 34 weeks for placenta praevia. Ultrasound scan showed a live pregnancy of 6+1 weeks with the gestation sac deeply embedded in the caesarean section scar. Myometrium could not be seen on the outer surface of the uterus and the pregnancy was closely applied to the bladder wall. A complete pregnancy percreta through the old scar was diagnosed. Although asymptomatic, the patient was offered termination of the pregnancy and a review of the literature was undertaken to decide how to safely manage the case. The patient initially underwent uterine artery methotrexate infusion via femoral catheters and embolization, however this was unsuccessful and a fetal heart was still present 7 days following treatment. After further counselling, the patient underwent intra-amniotic methotrexate and intra-cardiac lignocaine into the pregnancy, followed by alternate day intra-muscular methotrexate over 1 week, with alternate day folic acid. The treatment was successful and the patient went home 8 days after the initial treatment with falling beta-hCG levels. Discussion: The diagnosis of a complete pregnancy percreta through an old scar highlighted considerable risks for this patient. These included severe retro-vesical bleeding that would most likely require surgical resolution with the loss of the uterus and possible bladder damage. A number of problems may have been encountered if the pregnancy had continued, for example, severe placental insufficiency due to abnormal vascular supply, very pre-term delivery or intra-uterine demise. There was the risk of retro- or intra-vesical severe haemorrhage, and the likelihood of caesarean hysterectomy with bladder involvement as well as the risk of maternal loss of life due to uncontrollable haemorrhage, particularly after 20 weeks of gestation.