The causes of low sperm count are varied and often complex, spanning medical, environmental, hormonal, and lifestyle factors. Understanding these causes is crucial in addressing male infertility, as sperm production is sensitive to numerous internal and external influences.
What Causes Low Sperm Count?
Low sperm count means fewer than 15 million sperm per millilitre of semen, according to the World Health Organization. When sperm numbers drop below this, it becomes much harder to conceive. Knowing the causes helps doctors give better treatment. It also helps men make smart choices to improve their reproductive health.
At the biological level, problems in the testicles often cause low sperm count. The testicles make sperm, and when they don’t work well, sperm numbers drop. One common cause is varicocele, which means swollen veins in the scrotum. This condition raises the testicle temperature and harms sperm production and quality. Varicocele affects up to 40% of men with fertility problems and is treatable.
Another issue is undescended testicles. This happens when one or both testicles do not move down into the scrotum before birth. If doctors do not fix this early, it can cause low sperm count in grown men.
Infections That Lower Sperm Count
Infections can damage sperm-producing organs or block sperm from moving. Sexually transmitted infections like gonorrhoea and chlamydia cause inflammation or scarring. Mumps, especially after puberty, can also cause damage. Inflammation in the testicles (orchitis), epididymis (epididymitis), or prostate (prostatitis) reduces sperm numbers. If infections are not treated quickly, they may cause lasting harm.
Hormones and Low Sperm Count
The hormones control sperm production. Hormones like luteinising hormone (LH), follicle-stimulating hormone (FSH), and testosterone are key players. Problems in the pituitary gland, hypothalamus, or thyroid can stop the right signals from reaching the testicles.
For example, hypogonadism means low testosterone levels. This condition hurts sperm production and lowers sex drive. Genetic issues like Klinefelter syndrome or problems like pituitary tumors and long-term steroid use can cause this hormonal imbalance.
Genetic Causes of Low Sperm Count
Genetics also play a big role in low sperm count. Some men have extra or missing chromosomes. For instance, Klinefelter syndrome adds an extra X chromosome. This causes small testicles and poor sperm production. Another cause is Y chromosome microdeletions. These are tiny missing parts on the Y chromosome that affect sperm growth.
Doctors usually find these genetic problems through special tests. Men with these conditions often need assisted reproduction to have children.
Blockages That Affect Sperm Count
Sometimes sperm production is normal, but sperm can’t reach the semen. Blockages or missing tubes in the reproductive tract cause this. The vas deferens is the tube that carries sperm. It may be blocked by infections, surgeries like hernia repair, injuries, or it may be missing from birth.
This blockage is called obstructive azoospermia. Here, sperm count looks very low or zero, but the testicles still make sperm normally.
Environmental Causes of Low Sperm Count
Environmental toxins can harm sperm production. Pesticides, heavy metals like lead and mercury, and industrial chemicals disrupt sperm growth. People working in farming, painting, or factories face higher risks.
Some everyday items, such as plastics that release BPA (bisphenol A), can also change hormones and lower sperm count.
Lifestyle and Low Sperm Count
Lifestyle choices affect sperm health a lot. Smoking reduces sperm count, movement, and shape. It causes oxidative stress, which harms sperm. Drinking too much alcohol changes testosterone and hurts liver function, which affects hormones.
Using drugs like steroids, marijuana, or cocaine lowers sperm quality too. Some prescription medicines, like testosterone therapy, chemotherapy, and antidepressants, can also reduce sperm production as a side effect.
How Obesity Affects Sperm Count
Obesity is another cause of low sperm count. Fat cells raise estrogen and lower testosterone. This hormonal change harms sperm production. Fat also creates inflammation that may damage sperm DNA.
Obese men often have diabetes or metabolic syndrome. These health problems also lower fertility.
Heat and Sperm Production
Sperm needs a temperature below body heat to grow well. Using hot tubs, saunas, wearing tight underwear, or sitting long hours (like truck drivers or office workers) can heat the scrotum. This heat can cut sperm output.
Stress and Nutrition Impact on Sperm Count
Stress, both emotional and physical, can stop the body from releasing the hormones needed for sperm growth. Long-term stress also leads to poor habits like bad sleep, unhealthy food, and smoking, which lower fertility further.
A lack of important nutrients—such as zinc, folate, selenium, and antioxidants like vitamins C and E—also hurts sperm count and health.
Rare Causes: Autoimmune Reactions
In rare cases, the body attacks its own sperm. This autoimmune response makes antibodies that stick to sperm. These antibodies stop sperm from moving well or fertilising an egg.
Causes of Low Sperm Count are wide-ranging and often linked. Some causes improve with lifestyle changes or medical care. Others need advanced treatment. Knowing the causes is the first step to better reproductive health. It helps men take control and fight male infertility in a full and active way.
