ASAb (Anti-sperm antibodies) are a major cause of infertility and found in 9-36% of infertile couples.i They create an immune response to sperm and can affect either or both partners, but it’s a lot easier for men to get checked for antisperm antibodies as part of a standard semen sample test.
There’s normally a barrier between the man’s blood and his testes, and this separates his sperm from his immune system, because if sperm come into contact with the immune system it’s quite possible there will be an immune response to what are essentially abnormal cells (because they only contain half a normal cell’s DNA). Once an immune response has been triggered the acquired immune system makes anti-sperm antibodies and these will be in the mucous membranes of the urogenital tracts. From here the ASAb can physically attach themselves to sperm, which makes it extremely difficult for them to reach or fertilise an egg. The and significantly reduce the overall chances of a pregnancy:
- Over 50% of men with low sperm motility carry ASAbii
- About 66% of men with no live sperm carry ASAbiii
- Up to 70% of men who’ve had a vasectomy or a vasectomy reversal have ASAbiv
For men who know their testes or the area around it has had some sort of trauma then an ASAb test is a definite consideration, especially if the couple are struggling to get pregnant.
Women can also develop antibodies to sperm, and they’ll be found in her blood and/or cervical mucus. There are a number of ways they can develop, but once she has them they’re not specific to just one man’s sperm:
- Women can develop anti-sperm antibodies if their male partner has them
- The chances of a woman having antisperm antibodies rises with the number of male sexual partners she hasv