Site of ovulation and ectopic pregnancy.

In a study of 130 tubal pregnancies the relationships as to location of the corpus luteum, the implantation site, and the gross findings of the non-pregnant fallopian tube were analyzed. A contralateral corpus luteum was found in 20% of the cases. Hydrosalpinx, peritubal adhesions and/or thickening of the tubal wall were observed in 33% of the non-pregnant tubes. Grouping by implantation site--ipsilateral or contralateral corpus luteum--showed no statistical differences. The incidence of chronic pelvic inflammatory diseases was no greater in the subjects above 30 years of age and those having had more than 2 pregnancies. The results suggest that "tube locking" of the ovum, sometimesa result of previous tubal inflammatory disease, sometimes a result of supposed insufficiency of tubal peristalsis. was the major cause of tubal gestation. External migration of the ovum alone may not be an important factor in the genesis of tubal pregnancy.