Once the sperm are in the mucus, they can stay there for a few days. Thus the mucus acts as a sperm reservoir . Cervical mucus hostility is the inability of sperm to penetrate the cervical mucus. The significance of cervical mucus hostility is disputable among infertility specialists. Problems with cervical mucus usually cause no symptoms.
Mucus contains antisperm antibodies .
Abnormal or defective sperm.