Application of a sperm micro-immobilization test to cervical mucus in the investigation of immunologic infertility.

A complement-dependent sperm micro-immobilization test for antisperm antibodies in cervical mucus was evaluated in 195 infertile women. Positive tests were obtained among 17% of women with "unexplained" and 12% with an "organic" basis for their infertility. The results confirmed previous reports of the presence of cervical mucus antibodies in the absence of corresponding activity in serum. Non-complement-dependent sperm-immobilizing activity was also detected in the cervical mucus of several patients. During a follow-up period of 9 to 24 months, 10% of those with "unexplained" infertility who had complement-dependent sperm-immobilizing antibodies in their mucus became pregnant, compared with 29% of those without antibodies. The corresponding pregnancy rates for patients with "'organic" infertility were 18% and 11%. In four patients with positive tests who subsequently conceived, further tests failed to detect the persistence of the immobilizing activity.