Male infertility: tests and next steps

Who is usually assessed

Guidelines assess both partners when a couple has difficulty conceiving. According to the European Association of Urology (EAU), a male factor is found in about half of these couples. The World Health Organization lists the most common male causes as problems with ejaculation, absent or low numbers of sperm, and abnormal sperm shape or movement.

• Every man whose partner is having fertility investigations
• Men with a previous abnormal semen analysis
• Men with a history of undescended testes, testicular surgery or injury, a varicocele, or treatment such as chemotherapy
• Men who have difficulty with ejaculation

The semen analysis

The semen analysis measures the volume, the number and concentration of sperm, their movement (motility), their vitality and their shape (morphology). The findings are compared with the reference values in the WHO laboratory manual, which apply only when the laboratory follows the WHO methods.

Sperm counts vary from one sample to the next, so one abnormal analysis is not a diagnosis. NICE advises repeating it, ideally about three months later, to allow a full cycle of sperm production; if no sperm or very few are found, the repeat is done as soon as possible.

Further tests when the analysis is abnormal

Examination and hormones. After two abnormal analyses, NICE advises an examination of the scrotum and testes and suggests measuring testosterone and the pituitary hormones FSH and LH. The EAU recommends hormone tests for all men with a low or absent sperm count.

Genetic tests. When no sperm are found and there is no obvious cause, or when the count is very low, guidelines recommend a karyotype (a chromosome test) and a test for small deletions on the Y chromosome. A test for cystic fibrosis gene variants is advised when a blockage is suspected or the tubes that carry sperm (the vas deferens) are abnormal. Men with a genetic finding are offered genetic counselling; see genetic testing.

Tests not used routinely. NICE advises against routine antisperm antibody testing and against sperm DNA fragmentation testing. The EAU discusses DNA fragmentation testing in selected situations, so this question is still debated.

What the findings can mean

The next step depends on how marked the change is and on the female partner's findings. NICE advises considering ICSI, in which a single sperm is injected into each egg during IVF, when semen parameters are abnormal, taking the severity into account.

When there are no sperm in the ejaculate (azoospermia), the cause matters. With a blockage, it may be corrected surgically, or sperm may be retrieved surgically. Without a blockage, surgical sperm retrieval can find sperm in some men but not in all. A varicocele found on examination in a man with reduced semen quality may be treated, and a deficiency of the pituitary hormones that drive sperm production (hypogonadotropic hypogonadism) is treated with hormone injections.

Lifestyle and sperm quality

The EAU advises informing men that obesity, low physical activity, smoking and heavy drinking are linked with poorer sperm quality and lower testosterone. NICE notes that raised scrotal temperature is associated with reduced semen quality, although it is uncertain whether loose underwear helps, and advises reviewing medicines and drugs that can affect fertility, such as testosterone, anabolic steroids, finasteride and cannabis. Because sperm take about three months to form, a repeat analysis to see the effect of a change is usually done after that time.

The EAU does not recommend routine treatment with antioxidants, probiotics or hormone tablets for unexplained male infertility, and NICE advises against supplements or antioxidants to improve sperm DNA.