The production of sperm is a complex process and requires normal functioning of the testicles as well as the hypothalamus and pituitary glands – organs in your brain that produce hormones that trigger sperm production.
Once sperm is produced in the testicles, delicate tubes transport them until they mix with semen and are ejaculated out of the penis. Problems with any of these systems can affect sperm production. Also, there can be problems of abnormal sperm shape, movement or function.
Low sperm count can be caused by a number of health issues and medical treatments. Some of these include:
- Varicocele: A varicocele is a swelling of the veins that drain the testicle. It’s the most common reversible cause of male infertility. Although the exact reason that varicoceles cause infertility is unknown, it might be related to abnormal testicular temperature regulation. Varicoceles result in reduced quality of the sperm.
- Infection: Some infections can interfere with sperm production or sperm health or can cause scarring that blocks the passage of sperm. These include inflammation of the epididymis or testicles and some sexually transmitted infections, including gonorrhoea or HIV. Although some infections can result in permanent testicular damage, most often sperm can still be retrieved.
- Ejaculation Problems: Retrograde ejaculation occurs when semen enters the bladder during orgasm instead of emerging out of the tip of the penis. Various health conditions can cause retrograde ejaculation or lack of ejaculation, including diabetes, spinal injuries, and surgery of the bladder, prostate or urethra. Certain medications also might result in ejaculatory problems, such as blood pressure medications known as alpha-blockers. Some ejaculatory problems can be reversed, while others are permanent. In most cases, of permanent ejaculation problems, sperm can still be retrieved directly from the testicles.
- Antibodies that attack sperm: Anti sperm antibodies are immune system cells that mistakenly identify sperm as harmful invaders and attempt to destroy them.
- Tumours: Cancers and non-malignant tumours can affect the male reproductive organs directly, through the glands that release hormones related to reproduction, such as the pituitary gland, or through unknown causes. Surgery, radiation or chemotherapy to treat tumours also can affect male fertility.
Health, Lifestyle and Other Causes
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 those who do not smoke.
- Emotional Stress: Severe or prolonged emotional stress, including stress about fertility, might interfere with hormones needed to produce sperm.