Falloposcopic identification of a fimbrio-ovarian mucus connection as a possible mechanism for tubal oocyte capture.

Falloposcopy combined with laparoscopy was performed in 11 women during the late follicular phase of spontaneous menstrual cycles, and a preovular follicle was confirmed to be present in each case. The fimbrial end of the tube and the ipsilateral ovary containing the preovular follicle were suspended in a fluid environment of 200 ml of lactated Ringer's solution which acted as a support medium for visualization of tubal mucus and facilitated the endoscopy procedure. As the falloposcope was passed through the fimbrial opening, it was observed to carry clear, elastic and filamentous strands of mucus material from within the distal tubal lumen in 4 of 11 procedures. As these mucus strands were carried on the tip of the falloposcope to touch the surface of the ovary containing the preovular follicle, they attached, on contact, in all cases. The fimbrio-ovarian mucus bridge created was quite strong and could be stretched for up to 7 mm before it detached from the ovarian surface. The mucus attachment appeared to be equally secure over the preovular follicle and adjacent ovarian surfaces. These fimbrio-ovarian mucus connections, which have a high affinity for ovarian surface attachment about the time of ovulation, may play an important role in securing tubal oocyte capture in humans.