SPERM BINDING TO THE HUMAN ZONA-PELLUCIDA AFTER MIGRATION THROUGH HUMAN CERVICAL-MUCUS

During lactational amenorrhea a special type of cervical mucus, simila r to that found during the luteal phase, is produced. This mucus, howe ver, is able to support sperm migration. In the study described, the a bility of spermatozoa to bind to the human zona pellucida (hZP) after migration through periovulatory and post-partum mucus was studied. Muc us was obtained from exclusively breastfeeding women in amenorrhea at 30, 60, 120 and 180 days post-partum. Periovulatory mucus samples from normally cycling women were used as a control. Flat capillary tubes w ere filled with BWW culture medium at the top and cervical mucus at th e bottom. The tubes were immersed in a semen reservoir and the spermat ozoa allowed to migrate through the mucus for 3 h into the culture med ia. Then the spermatozoa were coincubated with 3-4 hZP for 30 min and the number of bound spermatozoa per zona was counted. Periovulatory ce rvical mucus had an average Insler score of 14 +/- 0.5 as compared to 4.6 +/- 0.4 for post-partum mucus. Spermatozoa recovered from periovul atory mucus were always able to bind to the hZP. Spermatozoa recovered from post-partum mucus, however, were able to bind to the hZP in only 68 +/- 7% of the cases. Moreover, spermatozoa recovered from post-par tum mucus bound to the ZP in lower numbers than did spermatozoa recove red from periovulatory mucus (p<0.03). These results suggest a greater ability of sperm-hZP binding after migration through periovulatory mu cus and they also indicate that sperm binding to the ZP is possible ev en after sperm migration through a low quality mucus.