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Causes of Male Infertility

There are various possible causes for male infertility, and few men with fertility problems have significant hormonal imbalances or show obvious signs or symptoms. However, some men are less fertile than other men simply because:

  1. They don’t make enough sperm that can reach an egg and fertilise it
  2. Their sperm either can’t fertilise an egg, or their DNA doesn’t create healthy pregnancies

The standard semen sample test is the first and often the last check that men have. It calculates sperm numbers and shapes to see if enough sperm are likely to reach an egg to fertilise it. There are also Additional sperm tests that can check whether sperm can fertilise eggs and are likely to create healthy pregnancies. These additional sperm tests are relatively new, and up to 80% of ‘unexplained male infertility are due to problems with sperm that only show up with these additional tests.

It’s always disappointing for men who provide poor semen samples, but significant improvements are possible for most. Thankfully our understanding of the causes of male infertility has increased a lot with ICSI and taught us practical ways to improve sperm quality.

10 Factors that reduce male fertility

  1. Obstructions in the testes or their tubes
  2. Raised testicular temperature
  3. Environment and lifestyle
  4. Illnesses
  5. Erectile and ejaculation problems
  6. Hormonal problems
  7. Oxidative stress
  8. “Other” factors
  9. Age
  10. Drugs

(1) Obstructions

These prevent semen from leaving the penis in an ejaculation:

  1. Physical trauma to the testes and scrotum has caused bleeding and swelling
  2. Twisting (torsion) of the testes and the tubes that lead from them
  3. Inherited abnormalities of the genital ducts that involve obstruct or restrict semen in the tubes
  4. From abdominal surgery, it’s usually for un-descended testes, hernia repair, prostate surgery, hydrocele correction, or a vasectomy
  5. After a sexually transmitted infection (usually Chlamydia or Gonorrhoea), which scar and block the tubes

(2) Raised testicular temperature

  1. Illnesses or infections that raise temperatures and reduce fertility for a while, including influenza (‘flu) and scarlet fever. There are also viruses like mumps that cause orchitis (swelling of the testes), which can cause long-term problems
  2. Tight clothing, being obese or lifestyle choices like heated seats all raise the temperature around the testes
  3. Varicoceles also raise testicular temperature because there’s more blood circulating there than normal

(3) Environmental and lifestyle factors

  1. Poor diets, caffeine, alcohol and cigarette smoking all increase toxins to sperm and reduce their health
  2. The many environmental or occupational pollutants that are toxic to sperm or alter their DNA
  3. Obesity or being overweight causes metabolic syndrome, and the inflammation involved in this reduces male fertility
  4. Cycling or motorcycling restricts blood flow and raises scrotal temperatures
  5. Chemotherapy, radiotherapy treatment or ionising radiation within the last two years will affect fertility
  6. Drugs such as anabolic-androgenic steroids, marijuana, cocaine, methamphetamines, and opium-based narcotics reduce male fertility. The act by altering the hypothalamic-pituitary-testicular axis, how sperm function, and the structure of the testes i
  7. There are many prescription drugs (drugs and male fertility) that also affect hormones and damage sperm

(4) Illnesses that lower male fertility

  1. Diabetes reduces male fertility because of the associated damage to the automatic nervous system and blood flow
  2. Hypertension (high blood pressure) can directly cause erectile issues, and the medication that’s taken to control it often does!
  3. Coronary artery disease can cause erectile problems and hardening of the arteries in the penis (as well as the heart), plus the drugs that treat it reduce fertility
  4. Neurological disorders (including multiple sclerosis, stroke, and spinal cord injury) can cause erectile and ejaculation problems
  5. Chronic renal failure causes a build-up of waste products in the body, and this reduces sperm quality and increases the likelihood of erectile problems
  6. Cancers affecting the genital tract or endocrine (hormone) systems can directly reduce fertility, plus the drug and radiation treatments to treat any cancer can reduce or stop sperm production
  7. Stress causes changes in the body’s hormonal balance and reduces fertility; of course, fertility-related anxiety can be a significant stressor

(5) Sexual problems (the main infertility issue for about 5% of couples)

  1. Erectile dysfunction (inability to get/maintain an erection adequate for intercourse)
  2. Premature ejaculation
  3. Failure to ejaculate, or “retrograde” ejaculation (where the semen goes into the bladder)
  4. The man is unable to penetrate the vagina for other reasons

(6) Hormonal problems

  1. Testosterone deficiency is a common cause of lower fertility. The root cause can be problems with either the testes, the pituitary gland or the hypothalamus. Testing is needed to work out which of these is the issue
  2. Hyperprolactinaemia is a condition caused by excess prolactin release from the pituitary gland. It’s usually discussed concerning female fertility as it stops menstrual cycles. However, it also can reduce male fertility and men who express milk from their nipples will have this condition
  3. Bodyweight impacts relative hormone levels as more fat increases leptin levels, increasing estrogen and reducing testosterone levels

(7) Oxidative stress

(8) Other factors

  1. Genetic problems are difficult to see, but 2-20% of infertile men have inherited factors such as Klinefelter’s syndrome
  2. The presence of leukocytospermia (white blood cells in the semen sample) indicates infections and high oxidative stress
  3. The presence of anti-sperm antibodies in semen samples
  4. Age as simply being an older man (over 45) can reduce fertility by up to 80%
  5. Higher levels of oxidative stress and “free radicals” that damage cells are found in semen samples from infertile men. They’re considered among the leading causes of male infertility
  6. Low concentrations of essential metals and the semen of infertile men often have lower concentrations than fertile men

(9) Male Age

(10) Drugs

morefertile® has information on treatments for male fertility and how to boost male fertility naturally.