Effect of microsurgical ampullary segmental reversal on fertilization in the rabbit.

Microsurgical reversal of a 1-2cm segment of mid ampulla was performed in rabbits. The fertility rate and location of ova were determined at 24 and 48 hours post coitum (hr p.c.). Oviducts in which a similar segment of mid ampulla was double-transected without reversal served as surgical controls. Contralateral oviducts in all animals served as unoperated controls. All ova and embryos recovered from oviducts with a reversed segment of mid ampulla had not been transported beyond the reversed segment at 24 or 48hr p.c. In contrast, all ova recovered from unoperated oviducts at 24 and 48hr p.c. and from double-transected oviducts at 48hr p.c. had undergone normal transport. We conclude that the ampullary isthmic junction and proximal ampulla are not unique, obligate sites for fertilization, that tubal ciliary activity is a minor determinant of sperm transport through the ampulla and that reversal of a 1-2cm segment of mid ampulla in the rabbit is consistent with normal sperm transport and fertilization. In contrast, ciliary activity prevents passage of ova or embryos past the reversed segment into the proximal oviduct.