Oligospermia

Oligospermia, or oligozoospermia, is a sperm concentration under the lower reference limit of 16 million/mL (total sperm number under 39 million in the whole ejaculate).

Severity is graded as mild (10 to 15 million/mL), moderate (5 to 10 million/mL) and severe (under 5 million/mL). Cryptozoospermia is sperm found only in the centrifuged pellet.

It is the commonest semen abnormality in infertile men, and often occurs with reduced motility and abnormal shape.

Pathophysiology. Causes:

• Varicocele: found in about 35% of men with primary infertility and about 80% of those with secondary infertility.
• Endocrine: hypogonadism, hyperprolactinaemia, thyroid disease and obesity.
• Genital tract infection and inflammation.
• Gonadotoxins and drugs: chemotherapy, radiotherapy, testosterone, anabolic steroids, sulphasalazine, alcohol, tobacco, cannabis, and heat exposure.
• Genetic: Y chromosome microdeletions, Klinefelter syndrome mosaicism and translocations.
• Cryptorchidism, torsion, mumps orchitis and systemic illness.
• Idiopathic, in 30 to 50%.

Total sperm count falls with prolonged febrile illness, with recovery over about 3 months.

Infertility after 12 months of regular unprotected intercourse. Most men have no other symptoms. Look for varicocele, small testes, gynaecomastia and signs of hypogonadism. History of cryptorchidism, genital infection, surgery, medications and occupational heat or toxin exposure.

• Two semen analyses at least 2 to 4 weeks apart after 2 to 7 days of abstinence, analysed within 1 hour. Lower reference limits: volume 1.4 mL, concentration 16 million/mL, total count 39 million, total motility 42%, progressive motility 30%, vitality 54%, normal forms 4%.
• FSH, LH, total testosterone and prolactin when concentration is under 10 million/mL, or when libido or sexual function is reduced.
• Karyotype and Y chromosome microdeletion testing when concentration is under 5 million/mL.
• Scrotal examination standing, with ultrasound for varicocele, testicular volume and masses.
• Semen culture and leucocyte count when infection is suspected. DNA fragmentation testing for recurrent pregnancy loss or failed assisted conception.
• Female partner assessment at the same time.

Differential diagnosis.

• Nonobstructive azoospermia (if repeat samples show none)
• Partial obstruction or ejaculatory duct obstruction
• Retrograde ejaculation or incomplete collection
• Hypogonadotropic hypogonadism
• Varicocele associated infertility
• Testicular tumour

• Lifestyle: reduce weight when body mass index is over 30, stop smoking and cannabis, limit alcohol, avoid heat exposure (saunas, tight clothing, laptops on the lap), and stop testosterone and anabolic steroids.
• Treat infection: doxycycline 100 mg orally twice daily for 7 to 14 days for chlamydia and mycoplasma, and culture directed antibiotics for others.
• Microsurgical subinguinal varicocelectomy for a palpable (clinical) varicocele with abnormal semen, couple infertility over 12 months and a female partner with normal or treatable fertility. Semen improves in about 60 to 70%, and pregnancy follows in about 30 to 40%. Percutaneous embolisation is an alternative.
• Hypogonadotropic hypogonadism: human chorionic gonadotrophin 1500 to 5000 IU subcutaneously or intramuscularly two to three times weekly, adding recombinant FSH 75 to 150 IU three times weekly for 3 to 6 months or more.
• Empirical drug treatment for idiopathic oligospermia has limited evidence:
  • Clomifene citrate 25 mg orally daily (maximum 50 mg daily) or tamoxifen 20 mg orally daily for 3 to 6 months, with testosterone and oestradiol checked at 4 to 6 weeks. Adverse effects: visual disturbance, mood change, headache, and rarely venous thrombosis.
  • Recombinant FSH 150 IU three times weekly for 3 to 6 months, with modest benefit.
  • Antioxidant supplements give inconsistent results and may be harmful at high doses, so they are not routine. If used, coenzyme Q10 200 to 300 mg daily for 3 to 6 months.
• Assisted reproduction by the post-wash total motile count:
  • Over 10 million: expectant management or intrauterine insemination.
  • About 5 to 10 million: intrauterine insemination.
  • Under about 5 million, or cryptozoospermia: in vitro fertilisation with intracytoplasmic sperm injection. Testicular sperm may be used in cryptozoospermia and with high DNA fragmentation.
• Cryopreserve semen before gonadotoxic treatment.

Monitoring. Repeat semen analysis 3 months after any intervention, which covers one cycle of sperm production, and every 3 months for up to 12 months. Reassess the couple at 6 months without pregnancy, or earlier when the female partner is over 35.

Referral and escalation. Refer to urology or andrology and a fertility unit for concentration under 10 million/mL, abnormal examination, abnormal hormones or female partner age over 35. Urgent referral for a testicular mass.