Other causes of low sperm count include:
- Drug use. Anabolic steroids taken to stimulate muscle strength and growth can cause the testicles to shrink and sperm production to decrease. Use of cocaine or marijuana might reduce the number and quality of your sperm as well.
- Alcohol use. Drinking alcohol can lower testosterone levels and cause decreased sperm production.
- Occupation. Certain occupations might be linked with a risk of infertility, including welding or those associated with prolonged sitting, such as truck driving. However, the data to support these associations is inconsistent.
- Tobacco smoking. Men who smoke might have a lower sperm count than do those who don’t smoke.
- Emotional stress. Severe or prolonged emotional stress, including stress about fertility, might interfere with hormones needed to produce sperm.
- Depression. Being depressed may negatively affect sperm concentration.
- Weight. Obesity can impair fertility in several ways, including directly impacting sperm and by causing hormone changes that reduce male fertility.
- Sperm testing issues. Lower than normal sperm counts can result from testing a sperm sample that was taken too soon after your last ejaculation; was taken too soon after an illness or stressful event; or didn’t contain all of the semen you ejaculated because some was spilled during collection. For this reason, results are generally based on several samples taken over a period of time.