An ectopic pregnancy in the upper retroperitoneum following in vitro fertilization and embryo transfer.

Thirty-seven days after successful embryo transfer, a chorionic vesicle was recovered from the upper abdominal retroperitoneal space in a patient presenting with an acute life-threatening hemorrhage. This is the first case report of a retroperitoneal ectopic pregnancy which, although uncommon, is a potentially fatal complication of in vitro fertilization-embryo transfer.