Teratozoospermia

Teratozoospermia is a low proportion of sperm with normal shape, defined as normal forms under 4% when strict criteria are used. The assessment needs a stained smear read by a trained observer.

Isolated mild or moderate teratozoospermia has a weak effect on natural conception. Rare monomorphic forms are genetic and severe.

Pathophysiology. Common causes: varicocele, genital tract infection, heat, smoking, alcohol, obesity, toxins and oxidative stress.

Rare genetic forms:

• Globozoospermia: round headed sperm without an acrosome, often due to deletion of DPY19L2. Sperm cannot activate the egg.
• Macrocephalic multiflagellar sperm: large heads and multiple tails, due to AURKC mutation, with sperm aneuploidy.
• Pinhead sperm, absent annulus and other flagellar defects.

Infertility with no other symptoms. Look for varicocele, infection and small testes. A family history of infertility suggests a genetic form.

• Semen analysis with a stained smear (Papanicolaou, Diff-Quik or Shorr stain) reporting percentage normal forms, head, midpiece and tail defects. Repeat on a second sample.
• Semen culture and leucocyte count, hormones (FSH, LH, total testosterone), and scrotal ultrasound for varicocele.
• Electron microscopy and genetic testing (DPY19L2, AURKC) when over 90% of sperm share the same abnormality.
• Sperm fluorescence in situ hybridisation for aneuploidy in macrocephalic sperm. Karyotype when severe.
• DNA fragmentation testing for recurrent loss or failed conception.

Differential diagnosis.

• Oligoasthenoteratozoospermia
• Varicocele
• Genital tract infection
• Necrozoospermia
• Primary ciliary dyskinesia
• Artefact from poor smear preparation or fixation

• Isolated mild or moderate teratozoospermia (normal forms 1 to 3%) with normal count and motility: reassurance, lifestyle correction and continued natural attempts for 12 months. Shape alone does not select the type of assisted reproduction.
• Lifestyle: stop smoking, reduce alcohol and weight, and avoid heat.
• Treat infection with culture directed antibiotics. Doxycycline 100 mg orally twice daily for 7 to 14 days for chlamydia and mycoplasma.
• Varicocelectomy for a palpable varicocele with abnormal semen and couple infertility.
• Antioxidants have inconsistent evidence and are not routine.
• Assisted reproduction:
  • Intrauterine insemination when the post-wash total motile count is over about 5 million and shape defects are moderate.
  • In vitro fertilisation with intracytoplasmic sperm injection for severe teratozoospermia with low count or motility, or failed insemination.
  • Globozoospermia: intracytoplasmic sperm injection with assisted oocyte activation (calcium ionophore).
  • Macrocephalic multiflagellar sperm: results are poor, and donor sperm should be discussed.
• Genetic counselling for monomorphic forms.

Monitoring. Repeat semen analysis 3 months after intervention. Review the couple at 6 to 12 months.

Referral and escalation. Refer to urology or andrology and a fertility unit for normal forms 0%, monomorphic defects or failed treatment. Urgent referral is rarely needed.