Immunological aspects of subfertility.

No significant relationship between semen quality [determined by standard sperm analysis and sperm-cervical mucus (CM) interaction testing in vivo and in vitro] and the presence of antisperm antibodies (ASA) [determined using three different methods] in serum samples of males and/or females of subfertile partnerships was found. These circulating ASA were not associated with reduced fertility in prospective studies. On the other hand, ASA in semen, particularly those of the IgA class, significantly impaired the ability of spermatozoa to penetrate CM and the fertility prognosis of the couple. ASA in CM must also be considered as a severe infertility factor but are a very rare cause of poor mucus quality.