Rupture is usually spontaneous. Isthmic pregnancies tend to rupture earliest, at 6 to 8 weeks’ gestation, due to the small diameter of this portion of the tube. Ampullary pregnancies rupture later, generally at 8-12 weeks. Interstitial pregnancies are the last to rupture, usually at 12-16 weeks, as the myometrium allows more room to grow than the tubal wall. Interstitial rupture is quite dangerous, as its proximity to uterine and ovarian vessels can result in massive hemorrhage.
After rupture, the conceptus may be resorbed or remain as a mass in the abdominal cavity or cul-de-sac. Rarely, if not damaged during rupture, it may implant elsewhere in the abdominal cavity and continue to grow.
Revision date: June 18, 2011
Last revised: by Janet A. Staessen, MD, PhD