Figure 1.

Schematic diagram summarizing the potential factors contributing to the development of tubal ectopic pregnancy.

Tubal ectopic pregnancy is caused by a combination of factors within the Fallopian tube which affect embryo-tubal transport and the tubal environment. Impaired Fallopian tube motility is caused by alterations in smooth muscle contractility and ciliary beat frequency. Changes to the tubal environment are thought to result in a setting fit for early embryo implantation. Factors inherent to the embryo itself, particularly during IVF, may also be predisposing to early implantation and tubal ectopic pregnancy.