The use of periovulatory human cervical mucus in human sperm capacitation and in-vitro fertilization of foreign eggs.

The time requirement of a routine in-vitro fertilization experiment using human spermatozoa and zona-free hamster oocytes is more than one working day. We have used a simple process of simultaneous sperm washing and capacitation before challenging them against oocytes. Spermatozoa were recovered up to 90 minutes from the proximal end of a column of periovulatory human cervical mucus into Brinster, Whitten and Whittingham's (B.W.W.) medium. Without any further capacitation 50 microliters of these spermatozoal suspension, in the concentration of 2.5-3 X 10(6)/ml, fertilized 81% of a total of 100 eggs. A dramatic decrease in the fertilization rate (18%) was observed when these spermatozoa were further capacitated in-vitro for five hours before actual egg incubation for three hours. Both selection and accelerated capacitation may contribute to this result.