Asthenozoospermia (or asthenospermia) is the medical term for reduced sperm motility. Complete asthenozoospermia, that is, 100% immotile spermatozoa in the ejaculate, is reported at a frequency of 1 of 5000 men. Causes of complete asthenozoospermia include metabolic deficiencies, ultrastructural abnormalities of the sperm flagellum (see Primary ciliary dyskinesia) and necrozoospermia.

It decreases the sperm quality and is therefore one of the major causes of infertility or reduced fertility in men. A method to increase the chance of pregnancy is ICSI. The percentage of viable spermatozoa in complete asthenozoospermia varies between 0 and 100%.

Sperm DNA fragmentation level is higher in men with sperm motility defects (asthenozoospermia) than in men with oligozoospermia or teratozoospermia. Among men with asthenozoospermia, 31% were found to have high levels of DNA fragmentation. As reviewed by Wright et al., high levels of DNA fragmentation have been shown to be a robust indicator of male infertility.

Hypoprolactinemia is associated with ovarian dysfunction in women, and metabolic syndrome, anxiety symptoms, arteriogenic erectile dysfunction, premature ejaculation, oligozoospermia (low concentration of sperm in semen), asthenospermia (reduced sperm motility), hypofunction of seminal vesicles, and hypoandrogenism in men. In one study, normal sperm characteristics were restored when prolactin levels were brought up to normal values in men with hypoprolactinemia.

Hypoprolactinemia can be a cause of lactation failure after childbirth.

Hypoprolactinemia is a medical condition characterized by a deficiency in the serum levels of the hypothalamic-pituitary hormone prolactin.