Low Sperm Count

Low sperm count, or oligozoospermia, is defined by World Health Organization reference values as a concentration below 15 million per millilitre, though concentration is only one parameter — motility, morphology and total count all matter, and total motile count often predicts outcomes better than concentration alone. Male factors contribute to roughly half of infertility cases, yet male assessment is frequently delayed while investigation focuses on the female partner. The most important practical fact is timing: spermatogenesis takes approximately 72 to 90 days, so any intervention needs about three months before a repeat semen analysis can show its effect, and a single abnormal result should always be repeated after a few weeks because values fluctuate considerably. Varicocele is the most common correctable cause and is present in a substantial proportion of men with abnormal parameters. Heat exposure matters more than most men realise: the testes function optimally a couple of degrees below core temperature, and laptops, hot tubs, saunas and prolonged sitting all raise scrotal temperature measurably. Smoking, heavy alcohol, anabolic steroid use and obesity all impair parameters, and anabolic steroids in particular can cause prolonged or permanent suppression. Testosterone therapy is a frequently missed cause: exogenous testosterone suppresses spermatogenesis and can render a man azoospermic.

• •Usually no symptoms other than difficulty conceiving
• •Inability to achieve pregnancy after 12 months of regular unprotected intercourse
• •Reduced facial or body hair suggesting hormonal causes
• •Small or soft testes
• •Swelling or a bag-of-worms feel in the scrotum suggesting varicocele
• •Erectile or ejaculatory difficulty in some cases
• •Reduced libido where testosterone is low
• •Previous testicular injury, surgery or undescended testis

• •Varicocele — the most common correctable cause
• •Heat exposure from hot tubs, saunas, laptops and prolonged sitting
• •Smoking and heavy alcohol use
• •Anabolic steroid use, which can cause prolonged or permanent suppression
• •Exogenous testosterone therapy, a commonly missed cause
• •Obesity
• •Genetic causes including Klinefelter syndrome and Y chromosome microdeletions
• •Undescended testis, past or present
• •Infection including mumps orchitis, chlamydia and gonorrhoea
• •Hormonal disorders: hypogonadotropic hypogonadism, hyperprolactinaemia, thyroid disease
• •Medications: sulfasalazine, some chemotherapy, cimetidine, finasteride
• •Cannabis and recreational drug use
• •Chronic illness, diabetes and coeliac disease
• •Occupational exposure to pesticides, solvents and heavy metals
• •Obstruction including vasectomy and congenital absence of the vas deferens

Spermatogenesis depends on hypothalamic GnRH driving pituitary FSH and LH, which stimulate Sertoli cells and testosterone production within the testis. Intratesticular testosterone must be far higher than blood levels for sperm production, which is precisely why exogenous testosterone — which suppresses LH and thus intratesticular production — reduces sperm counts. Heat impairs the temperature-sensitive enzymes of spermatogenesis. Varicocele raises scrotal temperature and causes oxidative stress. Reactive oxygen species damage sperm DNA, which is the mechanism behind smoking, obesity and inflammation-related impairment.