Low sperm count: What causes a decline in sperm count?

low sperm countMost men don’t really think about their sperm count, but unfortunately, it could be lower than normal. A low sperm count is also referred to as oligospermia. What’s classified as low is 15 million sperm per millimeter of semen or fewer than 15 million per ejaculation. Having a low sperm count decreases the odds that a single sperm will fertilize a female egg when attempting to procreate. Men with low sperm counts are still able to have children but may have a hard time successfully fertilizing their partner’s egg.

Sperm count declining in western men significantly: Study

A recent study and the first systematic review and meta-analysis of trends in sperm counts have found significant declines in sperm concentrations and sperm count among men in western countries.


The study was carried out by researchers from the Hebrew University-Hadassah Braun School of Public Health and Community Medicine in Jerusalem and the Icahn School of Medicine at Mount Sinai in New York.

The study in question screened 7,500 studies and conducted a meta-regression analysis on 185 studies that were done between the years of 1973 and 2011. They found a 52.4 percent decline in sperm concentration and a 59.3 percent decline in total sperm count. Both statistics were seen in men from North America, Europe, Australia, and New Zealand. Men from the South American, Asian, and African regions were not seen to have a significant decline, but this is thought to be attributed to the lack of data in these areas.

The data collected for this study used a broad scope and rigorous meta-regression methods to ensure accurate results. Estimates were done conservatively and controls for factors that might the decline, such as age, abstinence time, and selection of the study population, were all taken into account.

“Given the importance of sperm counts for male fertility and human health, this study is an urgent wake-up call for researchers and health authorities around the world to investigate the causes of the sharp ongoing drop in sperm count, with the goal of prevention,” said Dr. Hagai Levine, the lead author and Head of the Environmental Health Track at the Hebrew University-Hadassah Braun School of Public Health and Community Medicine.

A continuing decline in sperm counts is quite concerning, as the declined has remained consistent throughout the years analyzed. The researchers speculated that perhaps chemicals widely used in western culture are playing a yet unrealized role in low sperm counts. However, other theories include pesticide exposure, smoking, stress, and obesity.

Related: Many men unaware of their infertility risk factors: Study

What causes low sperm count?

Medical causes

  • Infectious disease – Sexually transmitted infections, inflamed testicles, and urinary tract infections can all prevent or block sperm protection. In some cases, they may even lead to infertility.
  • Varicocele – A swelling of the veins that drain the testicles and is the most common cause of reversible male infertility. The reason for varicocele development is not well documented, but might be related to abnormal testicular temperature regulation.
  • Retrograde ejaculation – Occurs when semen enters the bladder during orgasm instead of being sent out through the tip of the penis. This may be a complication of diabetes, spinal injuries, and surgery of the bladder, prostate, or urethra. Certain medicines may cause ejaculation problems as well.
  • Sperm antibodies – Immune cells falsely identify sperm as being harmful to the body and target them for destruction, leading to infertility.
  • Cancer or tumors – When occurring in the reproductive organs, cancers and tumors can affect fertility. However, there are regions in the brain that also play a role in sperm generation and if compromised, can also lead to infertility.
  • Hormone imbalances – The reproductive system is a delicate balance of the hormones produced by the hypothalamus, pituitary, and testicles. Any alterations in hormone levels may impair sperm production.
    Defects of the tubules that transports sperm – The many tubes that carry sperm can become blocked by a variety of different causes including inadvertent injury from surgery, prior infection, trauma, or abnormal development.
  • Chromosome defects – inherited disorders such as Klinefelter’s syndrome cause abnormal development of the male reproductive organs. Other genetic syndromes associated with infertility include cystic fibrosis, Kallmann’s syndrome, and Kartagener’s syndrome.
  • Celiac disease – A digestive disorder that is caused by sensitivity to gluten that may also lead to infertility. Fertility levels have been known to improve once adopting a gluten-free diet.
  • Medications – Drugs used during chemotherapy, anabolic steroids, certain antifungal and antibiotic medication, and anabolic steroids may impair sperm production and result in infertility.
  • Prior surgery – Vasectomy, inguinal hernia repairs, scrotal or testicular surgeries, prostate surgeries, and large abdominal surgeries can prevent you from having sperm to ejaculate. In most cases, these can be reversed.

Environmental cause

  • Industrial chemicals – Benzenes, toluene, xylene, herbicides, pesticides, organic solvents, painting materials, and lead exposure may contribute to low sperm counts
  • Heavy metal exposure – Lead or other heavy metal exposure can lead to infertility.
  • Radiation or x-rays – Radiation used in many diagnostic testing scenarios can reduce sperm production. It may take several years for sperm production to return to normal. High doses of radiation may even lead to permanent sperm reduction.
  • Overheating the testicles – The testicles need to be kept at a lower than normal body temperature to maintain normal sperm production and function. When the testicular temperature is not maintained at optimal ranges, sperm production can be impaired. While not studied extensively, frequent use of saunas or hot tubs might temporarily impair sperm counts. Also, wearing tight clothing and sitting with a laptop on your lap for prolonged sessions may increase the temperature of the scrotum and slightly reduce sperm production.

Health, lifestyle, and other causes

  • Drug use – The use of cocaine or marijuana might reduce the number and quality of sperm. It is well known that taking anabolic steroids to stimulate muscle strength and growth can cause the testicles to shrink, subsequently causing sperm production to decrease.
  • Alcohol use – Excessive alcohol consumption can lead to lower testosterone levels and cause decreases in sperm counts.
  • Occupation – Jobs that require prolonged sitting, such as truck driving, may be associated with an increased risk of infertility. However, data into this finding has not been consistent.
  • Tobacco smoking – It was found that men who smoke have lower sperm counts compared to non-smoking men.
  • Emotional stress – When prolonged due to factors in your life such as experiencing a trauma, it may interfere with various hormones levels involved in sperm production. Emotional stress can directly impact fertility.
  • Weight – Being obese causes many different hormone imbalances, including sex hormones. Obesity can be a factor for low sperm counts and infertility.
  • Sperm testing issues – Finding a low sperm count may simply be an issue of testing a sample that was taken too soon after your last ejaculation, taken too soon after an illness, or was part of a sample that didn’t contain all the semen that was ejaculated due to human error. For this reason, most facilities take several samples to ensure accuracy.

What are risk factors and complications of decline in sperm count

  • Taking certain medications
  • Having a prior vasectomy or major abdominal or pelvic surgery
  • Having a history of undescended testicles
  • Taking certain medications
  • Having had a prior vasectomy or major abdominal or pelvic surgery
  • Born with a fertility disorder or having a blood relative with a fertility disorder
  • Having certain medical conditions, such as tumors and chronic illnesses
  • Undergoing cancer treatments, such as radiation
  • Having certain past or present infections
  • Exposure to toxins
  • Overheating the testicles
  • Testicular trauma
  • Smoking tobacco
  • Drinking alcohol
  • Using certain illicit drugs
  • Being overweight

Complications caused by low sperm count may include:

  • Having to have surgery or other treatments to correct the underlying cause of a low sperm count
  • Stress due to the inability to conceive a child
  • Expenses involved in fertility procedures such as intro fertilization

Symptoms of low sperm count

Having a low sperm count for may present with additional signs that hint to a more serious underlying condition. These may be due to imbalances in sex hormones or due illness leading to reduced sperm counts. Developing on the underlying cause, symptoms will often follow suit. Not being able to reproduce may also lead to the development of psychological symptoms causes more stress to those affected.

Symptoms of low sperm count may include:

  • Inability to impregnate partner – Generally, a cause of concern when you and your partner have been trying for at least a year, which is considered a reasonable amount of time to become pregnant. While this can be due to a multitude of reasons, low sperm count will one aspect ruled out first.
  • Facial hair deficiency – Low sperm counts due to hormonal problems may also present with a lack of facial hair. Generally, this is not a good indicator for low sperm counts but may be seen as a clue to investigate further.
  • Lack of muscularity – A sign of male hormone abnormalities that may also be associated with diseases that are characterized by low male sex hormones, such as Klinefelter’s syndrome or genetic issues with the pituitary gland.

Infertility is not an issue most men think of but can be a truly stressful dilemma for you and your partner when trying to start a family. They are several options available to help boost fertility for both males and females, often with great success.



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Author Bio

Devon Andre has been involved in the health and dietary supplement industry for a number of years. Devon has written extensively for Bel Marra Health. He has a Bachelor of Forensic Science from the University of Windsor, and went on to complete a Juris Doctor from the University of Pittsburgh. Devon is keenly aware of trends and new developments in the area of health and wellness. He embraces an active lifestyle combining diet, exercise and healthy choices. By working to inform readers of the options available to them, he hopes to improve their health and quality of life.



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