What Causes Low Sperm Count and Poor Sperm Motility—and How Is It Treated?

Male infertility affects approximately 7% of all men, and among its most common causes are oligozoospermia (low sperm concentration) and asthenozoospermia (reduced sperm motility)—often referred to collectively as “low-count, low-motility” semen profiles. These conditions may occur independently or concurrently and are diagnosed through standardized semen analysis per World Health Organization (WHO) criteria: oligozoospermia is defined as a sperm concentration below 15 million/mL, while asthenozoospermia is diagnosed when less than 40% of sperm exhibit progressive motility—or less than 32% show forward progression.

The underlying etiologies are diverse and often multifactorial. Endocrine disorders—including hypogonadotropic hypogonadism, hyperprolactinemia, and thyroid dysfunction—can disrupt spermatogenesis. Varicocele, present in up to 40% of infertile men, induces testicular hyperthermia and oxidative stress, impairing both sperm production and function. Genetic factors such as Klinefelter syndrome (47,XXY), Y-chromosome microdeletions (particularly in the AZF regions), and cystic fibrosis transmembrane conductance regulator (CFTR) mutations also contribute significantly. Environmental and lifestyle influences—including chronic exposure to heat, tobacco smoking, excessive alcohol intake, obesity, and occupational toxins like pesticides or heavy metals—further compromise sperm quality.

Diagnosis begins with a comprehensive clinical evaluation: detailed reproductive history, physical examination focusing on testicular volume and varicocele detection, hormonal profiling (FSH, LH, testosterone, prolactin, and optionally inhibin B), and at least two properly collected and analyzed semen samples spaced ≥7 days apart. Genetic testing is recommended for men with sperm concentrations <5 million/mL or azoospermia. Scrotal ultrasound may confirm varicocele or identify structural abnormalities.

Treatment is tailored to the identified cause. Varicocelectomy—performed via microsurgical subinguinal approach—demonstrates the strongest evidence for improving semen parameters and natural conception rates, particularly in men with palpable varicoceles and abnormal semen analyses. Hormonal imbalances may be addressed with dopamine agonists for hyperprolactinemia or gonadotropin replacement in hypogonadotropic hypogonadism. Lifestyle modification remains foundational: weight loss in obese patients, smoking cessation, reduction of alcohol consumption, and avoidance of anabolic steroids or exogenous testosterone—which suppresses endogenous spermatogenesis. Antioxidant supplementation (e.g., coenzyme Q10, vitamin E, selenium) shows modest but statistically significant improvements in motility and concentration in randomized controlled trials, though benefits vary across individuals.

When medical or surgical interventions fail—or when baseline parameters remain severely impaired—intrauterine insemination (IUI) or in vitro fertilization (IVF) with intracytoplasmic sperm injection (ICSI) offer effective assisted reproductive options. ICSI bypasses functional sperm deficits by directly injecting a single viable sperm into an oocyte, making it especially valuable for men with profound asthenozoospermia or oligozoospermia. Referral to a reproductive urologist or fertility specialist is advised for persistent cases to ensure timely, evidence-based management and counseling on prognosis and family-building alternatives.