oligospermi

Oligospermia, or oligozoospermia, is a condition characterized by a lower-than-normal concentration of sperm in semen. The World Health Organization defines the lower reference limit for normal semen concentration as about 15 million sperm per milliliter; values below this threshold are termed oligospermia. The condition may occur with a reduced total sperm count per ejaculate and can be accompanied by differences in motility or morphology depending on the underlying cause.

Causes are diverse and can be classified as primary testicular disorders or secondary factors affecting sperm production or transport. Primary causes include genetic and congenital conditions; secondary factors include hormonal imbalances (such as low follicle-stimulating hormone or testosterone, elevated prolactin), varicoceles, infections of the reproductive tract, fever, and systemic illness. Lifestyle and environmental factors—smoking, heavy alcohol use, obesity, use of anabolic steroids, certain drugs, heat exposure from sauna or overheated environments, and occupational exposures—can contribute. In many cases, the cause is multifactorial or idiopathic.

Diagnosis rests on semen analysis conducted according to standard protocols. Typically two samples are collected on different days to confirm reduced concentration, following recommended abstinence periods. In addition to concentration, clinicians assess total sperm count, motility, and morphology, and may pursue hormonal, genetic, and anatomical evaluations to identify treatable conditions.

Treatment targets the underlying cause when possible. Lifestyle modifications and management of conditions such as varicocele or endocrine disorders may improve sperm parameters. When natural conception is unlikely, assisted reproductive techniques such as intrauterine insemination or in vitro fertilization with intracytoplasmic sperm injection (ICSI) are options. In some cases, medical or surgical interventions can improve outcomes, but there is no universal cure for oligospermia.

See also: male infertility, azoospermia, semen analysis.