Hypospermia
Hypospermia is a condition in which a man has an unusually low ejaculate (or semen) volume, less than 1.5 mL. It is the opposite of hyperspermia, which is a semen volume of more than 5.5 mL. It should not be confused with oligospermia, which means low sperm count. Normal ejaculate when a man is not drained from prior sex and is suitably aroused is around 1.5–6 mL, although this varies greatly with mood, physical condition, and sexual activity. Of this, around 1% by volume is sperm cells. The U.S.-based National Institutes of Health defines hypospermia as a semen volume lower than 2 mL on at least two semen analyses.
| -spermia, Further information: Testicular infertility factors |
| Aspermia—lack of semen; anejaculation |
| Asthenozoospermia—sperm motility below lower reference limit |
| Azoospermia—absence of sperm in the ejaculate |
| Hyperspermia—semen volume above upper reference limit |
| Hypospermia—semen volume below lower reference limit |
| Oligospermia—total sperm count below lower reference limit |
| Necrospermia—absence of living sperm in the ejaculate |
| Teratospermia—fraction of normally formed sperm below lower reference limit |
The presence of high levels of fructose (a sugar) is normal in the semen and originates almost entirely from the seminal vesicles. The seminal vesicles, which are major contributors to ejaculate volume, render semen viscous with a pH of 7.2–7.8. An acidic seminal pH (pH < 7.2) suggests damage to the seminal vesicles and an alkaline seminal pH (pH > 8) suggests prostatic involvement. In addition, low fructose may indicate problems in the prostate, while low semen pH may indicate problems related to the [seminal vesicles]. Obstruction of the seminal vesicles results in low semen volumes since they normally produce 70% of the seminal plasma.