Infertility is defined as the inability to achieve pregnancy after one year of unprotected intercourse. An estimated 15% of couples meet this criterion and are considered infertile, with approximately 35% due to female factors alone, 30% due to male factors, and 15% unexplained.
Male infertility is any health issue in a man that lowers the chances of his female partner getting pregnant.
Infertility in men can result from deficiencies in sperm formation, concentration, or transportation.
CAUSES OF MALE INFERTILITY
Sperm Disorders:The most common problems are with making and growing sperm. Sperm may:
- Not grow fully
- Be oddly shaped
- Not move the right way
- Be made in very low numbers (oligospermia)
- Not be made at all (azoospermia)
Sperm problems can be from traits you’re born with. Lifestyle choices such as smoking, drinking alcohol, and taking certain medications can lower sperm numbers. Other causes of low sperm numbers include long-term sickness (such as kidney failure), childhood infections (such as mumps), and chromosome or hormone problems (such as low testosterone).
Damage to the reproductive system can cause low or no sperm. About 4 out of every 10 men with a total lack of sperm (azoospermia) have an obstruction (blockage). A birth defect or a problem such as an infection can cause a blockage.
Varicoceles:Varicoceles are swollen veins in the scrotum. They’re found in 16 out of 100 of all men. They are more common in infertile men (40 out of 100). They harm sperm growth by blocking proper blood drainage. It may be that varicoceles cause blood to flow back into your scrotum from your belly. The testicles are then too warm for making sperm. This can cause low sperm numbers.
Retrograde Ejaculation:Retrograde ejaculation is when semen goes backwards in the body. They go into your bladder instead of out the penis. This happens when nerves and muscles in your bladder don’t close during orgasm (climax). Semen may have normal sperm, but the semen cannot reach the vagina.
Retrograde ejaculation can be caused by surgery, medications or health problems of the nervous system. Signs are cloudy urine after ejaculation and less fluid or “dry” ejaculation.
Immunologic Infertility: Sometimes a man’s body makes antibodies that attack his own sperm. Antibodies are most often made because of injury, surgery or infection. They keep sperm from moving and working normally. We don’t know yet exactly how antibodies lower fertility. We do know they can make it hard for sperm to swim to the fallopian tube and enter an egg. This is not a common cause of male infertility.
Obstruction: Sometimes sperm can be blocked. Repeated infections, surgery (such as vasectomy), swelling or developmental defects can cause a blockage. Any part of the male reproductive tract can be blocked. With a blockage, sperm from the testicles can’t leave the body during ejaculation.
Hormones:Hormones made by the pituitary gland tell the testicles to make sperm. Very low hormone levels cause poor sperm growth. Infertility can result from disorders of the testicles themselves or an abnormality affecting other hormonal systems including the hypothalamus, pituitary, thyroid and adrenal glands. Low testosterone (male hypogonadism) and other hormonal problems have a number of possible underlying causes.
Chromosomes:Sperm carries half of the DNA to the egg. Changes in the number and structure of chromosomes can affect fertility. For example, the male Y chromosome may be missing parts. Also, inherited disorders such as Klinefelter’s syndrome in which a male is born with two X chromosomes and one Y chromosome (instead of one X and one Y) cause abnormal development of the male reproductive organs. Other genetic syndromes associated with infertility include cystic fibrosis, Kallmann’s syndrome and Kartagener’s syndrome.
Medication:Certain medications can change sperm production, function and delivery. These medications are most often given to treat health problems like:
- Digestive problems
- High blood pressure
Overexposure to certain environmental elements such as heat, toxins and chemicals can reduce sperm production or sperm function. Specific causes include:
Industrial chemicals: Extended exposure to benzenes, toluene, xylene, pesticides, herbicides, organic solvents, painting materials and lead may contribute to low sperm counts.
Heavy metal exposure: Exposure to lead or other heavy metals also may cause infertility.
Radiation or X-rays: Exposure to radiation can reduce sperm production, though it will often eventually return to normal. With high doses of radiation, sperm production can be permanently reduced.
Overheating the testicles: Elevated temperatures impair sperm production and function. Although studies are limited and are inconclusive, frequent use of saunas or hot tubs may temporarily impair your sperm count.
Sitting for long periods, wearing tight clothing or working on a laptop computer for long stretches of time also may increase the temperature in your scrotum and may slightly reduce sperm production.
Health, lifestyle and other causes
Some other causes of male infertility 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 may temporarily reduce the number and quality of your sperm as well.
Alcohol use: Drinking alcohol can lower testosterone levels, cause erectile dysfunction and decrease sperm production. Liver disease caused by excessive drinking also may lead to fertility problems.
Tobacco smoking: Men who smoke may have a lower sperm count than do those who don’t smoke. Second-hand smoke also may affect male fertility.
Emotional stress: Stress can interfere with certain hormones needed to produce sperm. Severe or prolonged emotional stress, including problems with fertility, can affect your sperm count.
Depression: Research shows that the likelihood of pregnancy may be lower if a male partner has severe depression. In addition, depression in men may cause sexual dysfunction due to reduced libido, erectile dysfunction, or delayed or inhibited ejaculation.
Weight: Obesity can impair fertility in several ways, including directly impacting sperm themselves as well as by causing hormone changes that reduce male fertility.
Certain occupations including welding or those involving prolonged sitting, such as truck driving, may be associated with a risk of infertility. However, the research to support these links is mixed.
Mayo Clinic Staff (2011). Infertility – Symptoms and Causes. Retrieved from https://www.mayoclinic.org/diseases-conditions/infertility/symptoms-causes/syc-20354317 on 24th July 2019.
Palermo G. et al. Pregnancies after Intracytoplasmic Injection of Single Spermatozoon into an Oocyte. Lancet. 1992 Jul 4. 340(8810):17-8
Urology Care Foundation, American Urological Association 2019. Retrieved from https://www.urologyhealth.org/urologic-conditions/male-infertility on 24th July 2019.