What is the name of the condition where a fetus develops outside the uterus?

The condition where a fetus develops outside the uterus is called an ectopic pregnancy.

More precisely, an ectopic pregnancy begins when a fertilized egg implants somewhere other than the uterine lining. Most occur in a fallopian tube, which is why “tubal pregnancy” is sometimes used, although implantation can also occur in the cervix, ovary, abdomen, or a prior cesarean-scar site. The developing pregnancy cannot normally survive in these locations, and the growing tissue can rupture nearby structures and cause life-threatening internal bleeding.

Common symptoms include one-sided pelvic or abdominal pain, vaginal bleeding, dizziness, or shoulder pain from internal bleeding. Doctors commonly use serial human chorionic gonadotropin blood tests and ultrasound to investigate a suspected case. Treatment may involve monitoring, methotrexate, or surgery, depending on the pregnancy’s size, location, hormone levels, and the patient’s condition.

An ectopic pregnancy is not the same as a miscarriage: a miscarriage is a pregnancy loss inside the uterus, while an ectopic pregnancy is defined by abnormal implantation outside it. The first successful surgery for a ruptured ectopic pregnancy is associated with surgeon Robert Lawson Tait in 1883.