The fallopian tube is the most common location for pregnancies that implant outside the uterine cavity. In the minds of the lay public and many health professionals, tubal implantation is often considered synonymous with ectopic pregnancy. However, there are many other locations within the pelvis and abdominal cavity where a pregnancy could implant and grow. Cases of ectopic pregnancy have been described affecting organs as distant as the liver or omentum. It has been reported that approximately 7% of all ectopic pregnancies are located outside the fallopian tubes. Such pregnancies are often referred to as non-tubal ectopic pregnancies.
In recent years the incidence of ectopic pregnancy has increased owing to many factors such as improved sensitivity of urine pregnancy tests, better ultrasound diagnosis, wide use of assisted reproductive techniques and, possibly, the increased incidence of tubal damage caused by pelvic inflammatory disease. In addition, the increase in the number of surgical procedures involving the uterus, in particular the high rate of caesarean sections, has played an important role in the higher number of both tubal and non-tubal ectopic gestations.
Although non-tubal ectopic pregnancies are relatively rare, they are associated with significantly higher maternal morbidity and mortality rates compared with tubal ectopic pregnancies. This is primarily because of their tendency to remain clinically silent in early gestation and to present with acute, severe symptoms either late in the first trimester or during the second trimester of pregnancy.