Infertility is defined as the inability of a couple to achieve pregnancy after 12 months of regular, unprotected sexual intercourse. Normally, the probability of a pregnancy in healthy couples is about 85%.
Symptoms and causes
Infertility is attributable to either the man or the woman in 40% of the cases each; examination findings that may reduce the probability of a pregnancy are found in both partners in 20% of the cases.
Whereas the spermatozoa (sperm cells) are produced in the testicles themselves, the majority of the semen is produced by the seminal vesicles and the prostate. Disorders may affect either the production of spermatozoa in the testicles or the transport of spermatozoa from the testicles to the external urethral orifice.
Causes affecting sperm production include:
- Congenital genetic disorders
- Disturbances in the development of the testicles during pregnancy
- Retained testis in infancy
- Testicular damage as a result of injuries
- Testicular damage as a result of infections (bacteria, mumps (epidemic parotitis))
- Testicular varicose veins (varicoceles)
- Testicular tumours
Causes affecting sperm transport include:
- Congenital genetic disorders involving disturbances in the development of the vasa deferentia
- Occlusion of the vasa deferentia following inflammations
- Infertility following sterilisation (vasectomy)
- Injuries of the vasa deferentia, for example as a result of previous surgeries (inguinal hernia surgery)