III. Tubal abortion may occur, the ovum being discharged through the abdominal ostium into the peritoneal cavity.
IV. The ovum may be destroyed in the tube, gestation being stopped before rupture takes place.
Rupture of the tube is the rule in tubal pregnancy. The time of rupture depends upon the position of the ovum in the tube. It occurs somewhat later in the interstitial variety than when the ovum is situated in the free portion of the tube. Rupture in interstitial pregnancy commonly occurs before the fifth month. In the other forms of tubal pregnancy it occurs most usually before the end of the third month. In the latter class of cases the greatest number of ruptures occur during the second month.
Rupture is caused by the gradual thinning of the tube from distention. Rupture may take place suddenly, a large hole, through which the ovum escapes, being produced; or the rupture and discharge of the ovum may take place gradually without causing any acute symptoms.
When the rupture takes place between the layers of the broad ligament, the hemorrhage is usually not very profuse, as it is controlled by pressure of the structures that surround the blood. A broad-ligament hematoma is formed. The ovum may be destroyed as a result of the rupture, and no further lesions due to the development of gestation will arise. The hematoma, with the ovum, may in time be absorbed; or suppuration may occur, with the production of a pelvic abscess; or mummification, adipoceration, or lithopedion formation may take place in the fetus.
If the ovum is not destroyed by the rupture, it may continue to develop in the cavity formed by the tube and the broad ligament. The placenta may remain attached to the inner surface of the tube, or it may contract adventitious attachments to any of the surrounding structures—the surface of the uterus and the pelvic floor. The cavity occupied by the ovum may continue to enlarge, by the pushing aside of pelvic and abdominal organs, until full term is reached and spurious labor comes on.
In some cases a secondary rupture of the gestation-sac occurs, and the fetus is discharged into the peritoneal cavity.
When rupture of the tube into the peritoneal cavity occurs, the danger of fatal hemorrhage is very great. The majority of women die within forty-eight hours after this accident, unless relieved by immediate laparotomy. There is no surrounding pressure to control the hemorrhage, as in the case of rupture into the broad ligament. Sometimes the escaping ovum plugs the rent in the tube, and bleeding is checked in this way.
If the woman survive the effects of hemorrhage, she may die from peritonitis or from suppuration of the hematocele in the peritoneal cavity.
In exceptional cases, if the pregnancy be early, the blood and the ovum may be absorbed by the peritoneum, and spontaneous recovery occurs.