Oviduct contractile response to vaginal distension: identification of vagino-tubal reflex

The effect of vaginal distension on the oviduct contractile activity during penile thrusting at coitus could not be traced in the literature. We investigated the hypothesis that vaginal distension effects oviduct contraction, which assists in ovum transport along the oviduct.

Oviduct pressure was measured upon vaginal condom distension in 16 women (mean age 32.2+/-1.2 years) scheduled for abdominal hernia repair and oviduct ligation for sterilization. The test was repeated after individual anesthetization of the vagina and oviduct.

Ten milliliters vaginal distension effected pressure elevation of the ampullary (AO) and isthmic (IO) parts of the oviduct (p<0.01, p<0.01 respectively) and a decrease in intramural oviduct (IMO; p<0.01). Twenty milliliters distension further increased the pressure in the AO and the IO (p<0.001, p<0.001) and decreased it in IMO (p<0.001). Vaginal distension with greater volumes produced an oviduct pressure response similar to that with 20 ml distension (p>0.05). Vaginal distension of anesthetized vagina or oviduct did not evoke the oviduct pressure response, but saline infusion did.

Vaginal distension seems to produce oviduct motile activity as evidenced by oviduct pressure changes, which appear to assist in sperm-ovum transport and fertilization. These oviduct changes are suggested to occur reflexly through the "vagino-tubal reflex." Pathologic changes of the oviduct presumably interfere with this reflex action, a point that needs to be investigated.