The Leeds Teaching Hospitals NHS Trust

Common causes of subfertility

Nearly 1 in 6 couples will require some form of sub-fertility assistance. The exact prevalence of various conditions can vary demographically.

Please select an option from the menu to read more about the various causes of subfertility.

Causes of Female sub-fertility 

  1. Chronic pelvic inflammatory disease and tubal damage: 30%
  2. Male sub-fertility: 30%
  3. Endometriosis: 10-15%
  4. Ovulation disorders: 10-15%
  • polycystic ovaries
  • reduction in ovarian reserve
  • hyper-prolactinaemia
  • hypo or hyper thyroidism
  • other

5. Unexplained: 30%

6. Miscellaneous:

  • Fibroids
  • Endometrial polyps
  • Auto-immune disorders
  • Past treatments such as chemo or radiotherapy for cancers
  • Sterilisation
  • Genetic


Causes of male sub-fertility 

  1. Genito-urinary infections
  2. Undescended testicles
  3. Sterilisation or failure of reversal of vasectomy
  4. Hereditory or Genetic causes
  5. Orchidectomy for testicular tumours
  6. Past chemo or radiotherapy for cancers


Abnormal patterns 

In the majority of men, there is no constitutional abnormality of chromosome numbers i.e. the total numbers are normal as 46XY, but a structural aberration of the sex chromosome exists with either missing or modified genetic information on the Y chromosome. This chromosome is responsible for testicular development and sperm formation. In the event of loss of genetic material or its modification, men may have a genetically determined low sperm counts and subfertility. As the same Y chromosome will be passed on by ICSI to the male offspring, there may be a risk of passing the same defect to the male child and his future fertility may thus be similarly affected. There are no other known additional risk factors. We do not yet know all forms of gene deletions or mutations although active research is bringing more new information forward at a considerable pace.

In some men, there is an extra sex chromosome giving a pattern of 47XXY or 47XYY. The ICSI success rate in this case is low and variable. If successful the risk of similar genetic defect in the offspring is also not known.

If there is a constitutional chromosome aberration i.e. when there is an abnormality with the main 22 pairs, then the success rates after ICSI are also lower, there is an increased risk of miscarriage and, in ongoing pregnancies there will be a risk of congenital abnormality and/or mental retardation. Fortunately this situation is very rare in otherwise normal and healthy men.


Genetic or hereditary male sub-fertility 

Whilst most of the above listed causes of male sub-fertility are self-explanatory, genetic causes require some further explanation. This is because the treatment of male sub-fertility for genetic cause may require additional tests for assessment and may also have an influence on the outcome of your treatment. The incidence of chromosomal abnormalities is approximately 13.7% in azoospermic males (no sperm in the ejaculate) and 4.6% in men with low sperm counts. The incidence in men with normal sperm counts is 0.5%. Identifying these abnormalities may not only give us the reason for your problem but will also have an influence on the risk of having a similar abnormality in your children born after ICSI.

Normal chromosome pattern: This for every man is 46XY. There are 22 pairs of normal chromosomes (total 44) called the 'autosomes' and these are responsible for the general characteristics and bodily functions. The 23rd pair is the sex chromosome and in men this is expressed as XY, where X codes for female development and Y codes for development as a male. Females have two X-chromosomes and hence an XX pattern. In males the Y chromosome is the dominant one and this dictates development of the baby as a male.


Choice of treatments  

  • Where there is only a Female cause for Subfertility only IVF is needed.
  • Male Subfertility requires IVF in combination with ICSI.
  • Where Male & Female Subfertility is combined, IVF is performed in combination with ICSI.
  • Depending on the cause of male sub-fertility prior surgical sperm retrieval by PESA orMESAor TESE may be needed. We have separate information leaflets for this procedure.