In 1876 Parry collected 500 cases of extrauterine pregnancy from medical literature, but when Tait in 1883 first operated on a case of ruptured tubal pregnancy attention was called to the subject. It was better understood as coeliotomies (opening the abdomen) became common, and in 1892 Schrenck collected 610 cases that had been reported during the preceding five years. Küstner alone has operated on 105 cases in five years.
There has been much discussion among physicians as to the causes that arrest the fertilized ovum in the tube, but whatever these causes may be they do not affect the moral questions which come up in this article. There may be mechanical obstruction from peritoneal adhesions, or abnormal conditions resulting from inflammatory diseases of the tubes, ovaries, and the pelvic peritoneum, but no general cause that will explain all cases can be ascribed.
Tait denied the possibility of Ovarian Pregnancy, or a pregnancy where the ovum fastened to the ovary itself and developed there, but five fully established cases of this kind have been reported. Dr. J. Whitridge Williams, professor of Obstetrics at the Johns Hopkins University, in his textbook on Obstetrics (New York, 1903), collects twenty-five cases of ovarian pregnancy, where five cases are certain diagnoses, thirteen highly probable, and seven fairly probable. In these twenty-five cases ten foetuses reached full term, but four of the five certain cases ruptured at early periods.
It was formerly thought that primary abdominal pregnancy is quite common; that is, that the ovum is implanted on some organ within the abdomen itself, apart from the uterine adnexa. This is now looked upon as very doubtful, and such cases are probably secondary; that is, secondary to a pre-existing tubal pregnancy which has ruptured without great maternal hemorrhage and let the foetus grow within the peritoneal cavity.
The common form of extrauterine pregnancy is the Tubal Pregnancy. The ovum may be stopped in any one of the three parts of the tube, and we find Interstitial, Isthmic, or Ampullar Pregnancy. From these primary types, by rupture, secondary forms sometimes arise,—Tubo-abdominal, Tubo-ovarian, and Broad-ligament Pregnancy.
The interstitial form, that is, where the ovum is arrested in that part of the tube which passes through the wall of the uterus itself, is the rarest of the tubal pregnancies. Rosenthal (Ein Fall intranturaler Schwangerschaft. Centralbl. f. Gyn. 1297-1305) found it in only three per centum of 1324 cases of tubal pregnancy. Some deem the Isthmic variety the commonest. Dr. Howard Kelly (Operative Gynaecology) says he never met a case of Interstitial or Ovarian pregnancy in his practice. The interstitial form is especially liable to rupture with suddenly fatal hemorrhage.
About one-fourth of the cases of tubal pregnancy end within the first twelve weeks by rupture of the Fallopian tube. If the embryo is implanted in the interstitial end of the tube, the rupture (into the uterus, or into the abdominal cavity, or into the broad ligament) takes place later,—about the fourth month, or even considerably after that time. The reason for [{6}] the delay here is that the uterus grows with the foetus. If the foetus breaks into the uterus (a very rare occurrence), it is either expelled through the vagina almost immediately or it goes on like a normal pregnancy.
Tait was of the opinion that every case of tubal pregnancy results in a rupture of the tube not later than the twelfth week, but this opinion is no longer held. Very rarely a tubal pregnancy goes on without rupture to full term, as in the cases reported by Williams, Saxtorph, Spiegelberg, Chiari, and a few others.
Three-fourths, about seventy-eight per centum, of the cases of tubal pregnancy result in what is technically called "tubal abortion" instead of rupture. In tubal abortion the connection between the embryo and the tube-wall is broken by effusion of blood. If the separation is complete the effused blood pushes the embryo out through the fimbriated end of the tube into the abdominal cavity, and then the hemorrhage of the mother commonly ceases. Such an extrusion of the foetus is called a complete tubal abortion. If the connection between the foetus and the tube-wall is only partly severed, the ovum remains in the tube, and the maternal hemorrhage goes on. This is called incomplete tubal abortion.