The probability of an ectopic pregnancy with IVF is about 2%. So what is an ectopic pregnancy? It is when an embryo lays outside the uterus and it is called an ectopic pregnancy. IVF actually involves the union of sperm and egg outside the body to form a fertilized egg, which we then put back into the uterus to allow the embryo to take root, germinate and grow inside the uterus, also known as implantation. After the IVF embryo is placed back into the uterus, the embryo is wandering and it is possible that the embryo will not settle at the site where it was placed, especially in patients who have had a history of ectopic pregnancy and for whom the exact cause is not known, the embryo is particularly prone to wander towards the site of the fallopian tube and the horn of the uterus where the uterus joins the fallopian tube. In this group of patients, the embryo is often implanted in the horn of the uterus, where the uterus joins the fallopian tube, and the ectopic pregnancy occurs again. In patients where the fallopian tube is present, the embryo may wander into the fallopian tube and implant in the tube, which is the ectopic pregnancy.