The Causes of Male Infertility

Male infertility has many causes--from hormonal imbalances, to physical problems, to psychological and/or behavioral problems.  Moreover, fertility reflects a man’s “overall” health.  Men who live a healthy lifestyle are more likely to produce healthy sperm.  The following list highlights some lifestyle choices that negatively impact male fertility--it is not all-inclusive:

  • Smoking--significantly decreases both sperm count and sperm cell motility.

  • Prolonged use of marijuana and other recreational drugs.

  • Chronic alcohol abuse.

  • Anabolic steroid use--causes testicular shrinkage and infertility.

  • Overly intense exercise--produces high levels of adrenal steroid hormones which cause a testosterone deficiency resulting in infertility.

  • Inadequate vitamin C and Zinc in the diet.

  • Tight underwear--increases scrotal temperature which results in decreased sperm production.

  • Exposure to environmental hazards and toxins such as pesticides, lead, paint, radiation, radioactive

  • substances, mercury,  benzene, boron, and heavy metals

  • Malnutrition and anemia.

  • Excessive stress!

  • Modifying these behaviors can improve a man’s fertility and should be considered when a couple is trying to achieve pregnancy.

Hormonal Problems

  • A small percentage of male infertility is caused by hormonal problems.  The hypothalamus-pituitary endocrine system regulates the chain of hormonal events that enables testes to produce and effectively disseminate sperm.  Several things can go wrong with the hypothalamus-pituitary endocrine system:

  • The brain can fail to release gonadotrophic-releasing hormone (GnRH) properly.  GnRH stimulates the hormonal pathway that causes testosterone synthesis and sperm production.  A disruption in

  • GnRH release leads to a lack of testosterone and a cessation in sperm production.

  • The pituitary can fail to produce enough lutenizing hormone (LH) and follicle stimulating hormone

  • (FSH) to stimulate the testes and testosterone/sperm production.  LH and FSH are intermediates in the hormonal pathway responsible for testosterone and sperm production.

  • The testes’ Leydig cells may not produce testosterone in response to LH stimulation.

  • A male may produce other hormones and chemical compounds which interfere with the sex-hormone balance.

The following is a list of hormonal disorders which can disrupt male infertility:

Hyperprolactinemia

Elevated prolactin--a hormone associated with nursing mothers, is found in 10 to 40 percent of infertile males.  Mild elevation of prolactin levels produces no symptoms, but greater elevations of the hormone reduces sperm production, reduces libido and may cause impotence.  This condition responds well to the drug Parlodel (bromocriptine).

Hypothyroidism

Low thyroid hormone levels--can cause poor semen quality, poor testicular function and may disturb libido.  May be caused by a diet high in iodine.  Reducing iodine intake or beginning thyroid hormone replacement therapy can elevate sperm count.  This condition is found in only 1 percent of infertile men.

Congenital Adrenal Hyperplasia
 

Occurs when the pituitary is suppressed by increased levels of adrenal androgens.  Symptoms include low sperm count, an increased number of immature sperm cells, and low sperm cell motility.  Is treated with cortisone replacement therapy.  This condition is found in only 1 percent of infertile men.  

Hypogonadotropic Hypopituitarism

Low pituitary gland output of LH and FSH.  This condition arrests sperm development and causes the progressive loss of germ cells from the testes and causes the seminiferous tubules and Leydig (testosterone producing) cells to deteriorate.  May be treated with the drug Serophene.  However, if all germ cells are destroyed before treatment commences, the male may be permanently infertile.

Panhypopituitafism

Complete pituitary gland failure--lowers growth hormone, thyroid-stimulating hormone, and LH and FSH levels.  Symptoms include:  lethargy, impotence, decreased libido, loss of secondary sex characteristics, and normal or undersized testicles.  Supplementing the missing pituitary hormones may restore vigor and a hormone called hCG may stimulate testosterone and sperm production.

Physical Problems

A variety of physical problems can cause male infertility.  These problems either interfere with the sperm production process or disrupt the pathway down which sperm travel from the testes to the tip of the penis.  These problems are usually characterized by a low sperm count and/or abnormal sperm morphology.  The following is a list of the most common physical problems that cause male infertility.

Azoospermia

Azoospermia is the complete absence of sperm in the semen and as such means that a man will be completely infertile. The diagnosis of azoospermia is sometimes still made even though as many as 500,000 sperm per ml of semen may have been seen because it is extremely unlikely that the man will be able to father a child naturally with this number of sperm. Its incredible to realise that millions are needed for any chance of natural conception!

However, modern techniques such as ICSI (intra cytoplasmic sperm injection) mean that a man can still father his own biological child with expert medical help - This means that you must ask your doctor whether you have either (i) a very low sperm count so that you know you do at least make some sperm or (ii) absolutely no sperm at all which is the worst case scenario for any man to face.

In fact it is rare that a man has absolutely no sperm at all and as long as some sperm are produced it is possible nowadays to help couples have children via the ICSI procedure. So, if the doctor says you have azoospermia make sure you ask for a copy of the semen analysis results so that you can understand the situation.

Azoospermia occurs in about 2% of men in the general population. So whilst not common there are plenty of infertile men around - in the UK alone we would expect to find at least 300,000 men with azoospermia and many of these would appear extremely healthy and have no indication that any problem might exist !

Around 10-20% of men attending infertility centers will probably have azoospermia as well. This means that if you and your partner have been trying for a year or more to have a baby there is an increased risk that you may have a problem.

Oligospermia

Oligospermia is the leading cause of male fertility problems. A normal sperm count is 20 million or more per millimetre of semen. In order for conception to occur, a minimum of 60% of these sperm should have a normal shape (morphology) and normal forward movement (motility).

However, the above sperm count figure represents a general guideline, as some men with a higher sperm count have had difficulty conceiving while men with a sperm count lower than this number have been able to successfully get their partners pregnant.

Necrospermia

Necrospermia is a condition in which sperm are produced and found in the semen but are not alive and are unable to fertilize eggs. That over 40% sperms are dead in the semen analysis indicates necrospermia.

Necrospermia is a condition in which sperm are produced and found in the semen but are not alive and are unable to fertilize eggs. That over 40% sperms are dead in the semen analysis indicates necrospermia.

Necrospermia is still a poorly documented cause of male infertility. Among infertile subjects, the incidence reported in the literature is 0.2 to 0.48 per cent. We undertook a retrospective study to contribute to the comprehension of this abnormality. Histories, physical examination, analysis of the semen and hormonal dosages performed in necrozoospermic subjects were reviewed. We observed that in patients with necrospermia in at least three semen samples, infections represent 40 per cent of aetiologies. In 20% of the whole population, no aetiology was observed, but abnormalities of the epididymis function were suggested. Through this study, we suggest an aetiological classification and practical guidance in case of necrozoospermia.

Antisperm Antibodies

Necrospermia is still a poorly documented cause of male infertility. Among infertile subjects, the incidence reported in the literature is 0.2 to 0.48 per cent. We undertook a retrospective study to contribute to the comprehension of this abnormality. Histories, physical examination, analysis of the semen and hormonal dosages performed in necrozoospermic subjects were reviewed. We observed that in patients with necrospermia in at least three semen samples, infections represent 40 per cent of aetiologies. In 20% of the whole population, no aetiology was observed, but abnormalities of the epididymis function were suggested. Through this study, we suggest an aetiological classification and practical guidance in case of necrozoospermia.

Semen

This condition may be treated by several methods such as cortisone, sperm washing which increases sperm concentration, intrauterine insemination, or in vitro fertilization. Semen volume - the amount of fluid that makes up the semen

  • Sperm count - the number of sperm present in a standard volume. A normal sample contains more than 20 million sperm per milliliter.

  • Motility - the percent of sperm moving when the semen is examined under the microscope. Normal is defined as >50% motile.

  • Progression - the forward movement of sperm cells

  • Viability - the percent of live sperm

  • Sperm morphology or shape

Additional semen contents, such as white blood cells, are an indication of infection. Less than five white blood cells per high power field is considered normal.

Semen

Average volume of ejaculate

   0.5 to 1 teaspoon

Chief ingredient

   Fructose sugar

Caloric content

5 calories per teaspoon

Protein content

6 milligrams per teaspoon

Average number of ejaculatory spurts

3 to 10

Average interval of ejaculatory contractions

0.8 seconds

Farthest medically recorded ejaculation

11.7 inches

Variocoele

 

A varicocele is an enlargement of the internal spermatic veins that drain blood from the testicle to the abdomen (back to the heart) and are present in 15% of the general male population and 40% of infertile men.  These images show what a variocoele looks like externally and internally.

A varicocele develops when the one way valves in these spermatic veins are damaged causing an abnormal back flow of blood from the abdomen into the scrotum creating a hostile environment for sperm development.  Varicocoeles may cause reduced sperm count and abnormal sperm morphology which cause infertility.  Variococles can usually be diagnosed by a physical examination of the scrotum which can be aided by the Doppler stethoscope and scrotal ultrasound.  Varicocoele can be treated in many ways (see treatment section), but the most successful treatments involve corrective surgery.

Damaged Sperm Ducts

Seven percent of infertile men cannot transport sperm from their testicles to out of their penis.  This pathway may be blocked by a number of conditions:

  • A genetic or developmental mistake may block or cause the absence of one or both tubes (which transport the sperm from the testes to the penis).

  • Scarring from tuberculosis or some STDs may block the epididymis or tubes.

  • An elective or accidental vasectomy may interrupt tube continuity.

Torsion

Is a common problem affecting fertility that is caused by a supportive tissue abnormality which allows the testes to twist inside the scrotum which is characterized by extreme swelling.  Torsion pinches the blood vessels that feed the testes shut which causes testicular damage.  If emergency surgery is not performed to untwist the testes, torsion can seriously impair fertility and cause permanent infertility if both testes twist.

Infection and Disease

Mumps, tuberculosis, brucellosis, gonorrhea, typhoid, influenza, smallpox, and syphilis can cause testicular atrophy.  A low sperm count and low sperm motility are indicators of this condition.  Also, elevated FSH levels and other hormonal problems are indicative of testicular damage.  Some STDs like gonorrhea and chlamydia can cause infertility by blocking the epididimis or tubes.  These conditions are usually treated by hormonal replacement therapy and surgery in the case of tubular blockage.

Testicular Failure

This generally refers to the inability of the sperm-producing part of the testicles (the seminiferous elithelium) to make adequate numbers of mature sperm. This failure may occur at any stage in sperm production for a number of reasons. The testicle may completely lack the cells that divide to become sperm (Sertoli Cell-Only Syndrome). There may be an inability of the sperm to complete their development (maturation arrest). Sperm may be made in such low numbers that few, if any, successfully travel through the ducts and into the ejaculated fluid (hypospermatogeneses). This situation may be caused by genetic abnormalities, hormonal factors, or varicoceles.

Even in the case where the testes are only producing low numbers of sperm, the sperm may be harvested and used in conjunction with advanced reproductive techniques to attempt a pregnancy.

Cryptorchidism

Cryptochiridism may be a cause of testicular failure. When a baby boy is born without the testes having fully descended into the scrotum, the condition is known as cryptorchidism.

Since the testes are very sensitive to temperature, if they do not descend into the scrotum prior to adolescence, they will stop producing sperm altogether. In fact, they have a higher rate of malignancy. The current recommendation is that at approximately one year of age, if the testes have not descended by themselves, they be brought down surgically.

Cryptorchidism is often associated with male factor infertility. Eight-one percent of men who have a single testis that is cryptorchid have normal fertility. However, approximately, 50% of men who have bilateral cryptorchidism have normal fertility. This may be due both to something inherent in the testes, to the surgery, or to damage done by not having the testes brought down in time.

Mumps

Mumps is the best-known cause, but is not the only one. Mumps will only affect fertility if it causes orchitis and, even then, only rarely. Undescended testicles (cryptorchidism) are another common cause of failure of sperm production. Male infants and children are routinely examined to identify this problem, as future fertility can only be preserved if surgical treatment to fix the testicles in the scrotum is performed in early childhood. Even surgery in infancy does not guarantee future fertility.

Orchitis

Orchitis is an inflammation of testicle tissue. Mumps orchitis, a complication of the childhood viral disease, is the most typical example of complication in childhood; however, some men who get mumps with swelling of the parotid gland (the saliva-producing glands in the cheeks) will experience an inflammation in one or sometimes both testicles.

Klinefelter’s Syndrome

Is a genetic condition in which each cell in the human body has an additional X chromosome--men with Klinefelter’s Syndrome have one Y and two X chromosomes.  Physical symptoms include peanut-sized testicles and enlarged breasts.  A chromosome analysis is used to confirm this analysis.  If this condition is treated in its early stages (with the drug hCG), sperm production may commence and/or improve.  However, Klinefelter’s Syndrome eventually causes all active testicular structures to atrophy.  Once testicular failure has occurred, improving fertility is impossible.  

Retrograde Ejaculation

Is a condition in which semen is ejaculated into the bladder rather than out through the urethra because the bladder sphincter does not close during ejaculation.  If this disorder is present, ejaculate volume is small and urine may be cloudy after ejaculation.  This condition affects 1.5 percent of infertile men and may be controlled by medications like decongestants which contract the bladder sphincter or surgical reconstruction of the bladder neck can restore normal ejaculation.

Psychological/Physical/Behavioral Problems

Several sexual problems exist that can affect male fertility.  These problems are most often both psychological and physical in nature:  it is difficult to separate the physiological and physical components.

Erectile Disfunction (ED)

Also known as impotence, this condition is common and affects 20 million American men.  ED is the result of a single, or more commonly a combination of multiple factors.  In the past, ED was thought to be the result of psychological problems, but new research indicates that 90 percent of cases are organic in nature.  However, most men who suffer from ED have a secondary psychological problem that can worsen the situation like performance anxiety, guilt, and low self-esteem.  Many of the common causes of impotence include:  diabetes, high blood pressure, heart and vascular disease, stress, hormone problems, pelvic surgery, trauma, venous leak, and the side effects of frequently prescribed medications (i.e. Prozac and other SSRIs, Propecia).  Luckily, many treatment options exist for ED depending on the cause--these will be discussed in the treatment section.

Premature Ejaculation

Is defined as an inability to control the ejaculatory response for at least thirty seconds following penetration.  Premature ejaculation becomes a fertility problem when ejaculation occurs before a man is able to fully insert his penis into his partner’s vagina.  Premature ejaculation can be overcome by artificial insemination or by using a behavioral modification technique called the “squeeze technique” which desensitizes the penis.

Ejaculatory Incompetence

This rare psychological condition prevents men from ejaculating during sexual intercourse even though they can ejaculate normally through masturbation.  This condition sometimes responds well to behavioral therapy; if this technique does not work, artificial insemination can be employed using an ejaculate from masturbation.

General Medical Disorders that Reduce Fertility

There are several conditions that may reduce fertility

  • Fever
    Influenza (flu), pneumonia, or even a severe cold can cause a high fever, which will adversely affect sperm production and quality. These changes usually recover over a few weeks.

  • Diabetes
    In the longer term, diabetes can cause problems with erection and ejaculation through causing damage to the function of the 'automatic nervous system'.

  • High Blood Pressure
    Hypertension (high blood pressure) can cause problems with erection, either directly or as a side effect of medication.

  • Coronary Artery Disease
    Coronary artery disease can cause problems with erection. This could be due to generalised hardening of the arteries, in the penis as well as the heart, or to drugs used in the treatment of heart problems.

  • Neurological Disorders
    Multiple sclerosis, stroke, and spinal cord injury and disease can all cause problems with erection and ejaculation.

  • Kidney Disease
    Chronic renal failure, which results in a build up of waste products in the body, can adversely affect sperm quality and fertility. It can also cause erection problems.

  • Cancers
    That affect the genital tract or endocrine (hormone-producing) systems may directly reduce fertility. Otherwise, drugs and radiation used to treat cancer may severely reduce sperm production or even stop it altogether. Stress (see below) may also have an effect.

  • Alcoholism
    Alcohol is toxic to sperm and overuse of alcohol can reduce sperm quality and fertility.

  • Stress
    Stress causes several hormonal changes in the body that can affect fertility. Stress can have many causes, including anxiety over fertility problems.

  • General Health and Lifestyle
    A man's general health and lifestyle may affect fertility. Some common causes of infertility related to health and lifestyle include:

  • Emotional Stress
    Stress may interfere with certain hormones needed to produce sperm. Your sperm count may be affected if you experience excessive or prolonged emotional stress. A problem with fertility itself can sometimes become long term and discouraging, producing more stress. Infertility can affect social relationships and sexual functioning.

  • Malnutrition
    Deficiencies in nutrients such as vitamin C, selenium, zinc and folate may contribute to infertility.

  • Obesity
    Increased body mass may be associated with fertility problems in men.

  • Cancer and its Treatment
    Both radiation and chemotherapy treatment for cancer can impair sperm production, sometimes severely. The closer radiation treatment is to the testicles, the higher the risk of infertility. Removal of one or both testicles due to cancer also may affect male fertility.

  • Pesticides and other Chemicals
    Herbicides and insecticides may cause female hormone-like effects in the male body and may be associated with reduced sperm production and testicular cancer. Lead exposure may also cause infertility.

  • Substance Abuse
    Use of cocaine or marijuana may temporarily reduce the number and quality of your sperm.

  • Other Medical Conditions
    A severe injury or major surgery can affect male fertility. Certain diseases or conditions, such as diabetes, thyroid disease, Cushing's syndrome, or anemia may be associated with infertility.

  • Age
    A gradual decline in fertility is common in men older than 35.

Possible Causes

General Health

     

Even in the absence of systemic illness, poor general health will impair fertility.

  • Aim for an ideal BMI.

  • In those who are overweight (BMI 25 to 30) and obese (BMI>30) there is a relationship between the degree of excessive weight and poor quality and quantity of sperm.11

  • The adverse effects of smoking on male fertility are inadequately appreciated.12,13

  • Excessive alcohol consumption also impairs fertility.14

  • The effect of lower levels of consumption does not seem to have been adequately researched.

  • Male exposure to recreational drugs, toxic substances in the workplace and ionising radiation do not seem to have a significant effect on fertility, but may cause an increase in congenital malformations, spontaneous abortions, fetal resorption, low birth weight infants, increase in childhood cancers, developmental and behavioural abnormalities.15

  • Past abuse of anabolic steroids may cause infertility.16

  • It is reasonable to suggest that anyone intent on embarking on the rigours of fatherhood should show responsibility with regard to alcohol, drugs and other aspects of lifestyle.

Disorders of the Testis and Spermatogenesis

These may be structural or hormonal.

  • Persistent azoospermia is incompatible with fertility.

  • Whilst a low sperm count is a poor prognostic feature, and the lower the count the worse the prognosis, it is not totally incompatible with fertility.

  • Klinefelter's syndrome with karyotype XXY is associated with hypogonadism and disorders of spermatogenesis.

  • Failure of descent of the testes has already been mentioned.

  • Early orchidopexy is required to permit normal development.

  • Testicular feminisation is when there is resistance to the virilising effects of androgens and a child with an XY karyotype appears as a girl.

  • This can be much less complete and more limited resistance to androgens can lead to poor development of the testes.17

  • Testicular tumours are usually treated by orchidectomy, possibly followed by radiotherapy.

  • In men presenting with infertility and abnormal semen analysis there is a 20-fold increase in the risk of testicular cancer.18

  • Treatment of testicular cancer reduces fertility by 30%, but this is most marked in those who have received radiotherapy.19

  • Traditional teaching has been that varicocele results in a warmer environment for the testis and that this impairs spermatogenesis and fertility.

  • There has been much dispute over the years about the significance of varicocele, but an interesting recent observation is that varicocele is more associated with secondary than primary infertility and so it may be responsible for a premature decline in sperm count.20

  • Trauma can cause testicular damage.

  • Pituitary tumours will displace or destroy normal tissue and the production of FSH and LH is often the first to be affected.

  • Panhypopituitarism is also called Simmond's disease.

  • Hyperprolactinaemia rarely present with galactorrhoea in men.

  • In one study it caused gynaecomastia in 8% of men but impotence in 30%.21

  • The control of prolactin is unlike the other releasing factors in that it is controlled by an inhibiting rather than a releasing factor from the hypothalamus into the hypothalamic-pituitary portal circulation.

  • It is also released in response to thyrotrophin releasing factor, as is TSH, and so it is elevated if thyroxine is low.

  • The pituitary gland may be responsible for other disorders such as Cushing's syndrome.

  • Low levels of testosterone are found in 20 to 30% of infertile men, but giving testosterone does not improve fertility.16

Disorders of the Genital Tract

  • Failure of adequate differentiation of the embryonic testis can cause failure of proper development of the spermatic ducts.

  • In vasectomy the objective is to interrupt the vas deferens and it may be possible to reunite this in an attempt to reverse the procedure but the success rate as measured by successful pregnancy is poor.

  • Congenital urogenital abnormalities such as hypospadias can cause problems. It tends to deposit the semen in the acid environment of the vagina rather than near the friendlier environment of the cervix.

  • Does the possession of just one testis impair fertility?

  • In theory it should reduce the sperm count by 50% that would have no significant effect on fertility.

  • However, the loss of the testis may have been associated with other problems that may have had an adverse effect on the other one such as chemotherapy or radiotherapy for cancer.

  • Where a single testis has been lost or failed to develop in the absence of other problems, the presence of just one testis does not have an adverse effect on fertility.