The experimental production of an early stage of extrauterine pregnancy

Abstract

In former experiments I had shown that it is apparently impossible to produce experimentally an extrauterine pregnancy in the guinea pig. 1 Neither ligation of the fallopian tubes at the juncture with the uterus, nor incision into the tubes or wall of the uterus at various periods of the sexual cycle led to the development of an extrauterine pregnancy. In another series of experiments I had shown that in the guinea pig only the mucosa of the uterus is able to produce a decidua under the influence of experimentally applied stimuli. In the human organism where extrauterine pregnancy occurs, decidua can to some extent form also at certain places outside of the uterine mucosa. It is, therefore, probable that one of the factors upon which the development of an extrauterine pregnancy depends is the capability of the tissue, into which the ovum penetrates, to develop decidual tissue which presents to the ovum an adequate soil for development.

In an experiment carried out recently I was able to show that it is possible to produce experimentally the first stages of an extrauterine pregnancy in the guinea pig, that however the development of embryo and placenta outside the uterus ends prematurely.

Incisions were made into the uterus of a guinea pig two days, sixteen hours after copulation. The incision reached upwards through the greater part of both horns. Eighteen days after copulation, examination of ovary and uterus showed that a new ovulation had taken place approximately three days previously, fifteen days after the preceding copulation. On the peritoneal side of the left horn of the uterus, near the fallopian tube was embedded superficially in the tissue a young embryo in which structures appear which resemble the neural canal, coelomic and enteric cavities and the anlage of the blood vessels.