A physical examination may be conducted to review easy to identify physical issues such as:
- Undescended testis. When the testis has not reached its normal position in the scrotum which stops it from functioning properly and may stop it from producing sperm.
- Testicular size. Small volume testes are associated with poor sperm production.
- Whether the tubes that carry sperm from the testes to the outside world are present or not.
A semen analysis will look for the following sperm features:
- Number (concentration) and movement (motility) of sperm. A healthy ejaculate contains greater than 40 million sperm with at least half of them swimming appropriately. If a man isn’t producing enough sperm, the chance of conception is significantly reduced.
- Shape (morphology). A healthy sperm has an oval head and a long tail which propels it forward. Sperm with abnormal shaped heads or curled or double tails are less likely to fertilise an egg.
A more detailed analysis of sperm can also include:
- DNA quality. The genetic information (DNA) carried in the sperm head – that meets with equivalent information of the egg after fertilisation – also needs be healthy. If there is DNA damage this can lead to poorly developing embryos and a risk of miscarriage. A regular turnover of sperm leads to less DNA damage so regular ejaculation is important.
Occasionally these features are all normal but the man’s immune system accidentally makes anti-sperm antibodies which prevent the natural binding between sperm and eggs.
For patients who have had recurrent miscarriage or have a genetic condition in their family, a Fertility Specialist may review both partners for chromosome abnormalities. Should abnormalities be detected, it may indicate that Pre-implantation Genetic Diagnosis or Pre-implantation Genetic Screening is required.
Even without any obvious family history, all couples planning pregnancy should consider having testing to ensure that they both don’t carry the same quiet genetic (recessive) condition. Many of us carry one recessive condition which in itself doesn’t cause disease, however if both partners carry the same recessive gene (examples include cystic fibrosis and spinal muscular atrophy) – then that couple have a 1 in 4 chance of having a baby with a serious medical disorder. Your Fertility Specialist will usually offer this testing which is undertaken by an external pathology company.
A Fertility Specialist or GP may order an ultrasound to check for:
- Obstructions - preventing the sperm from leaving the male reproductive system.
- Scrotal varicocele - large veins (varicose veins) wrapping around one or both of the testicles which may impair the ability of the scrotum to cool down and therefore affects sperm quality.
- Any pre-cancerous change in the testes – men with very low sperm counts have a higher risk for this.