Causes of infertility

The causes of infertility vary between individuals, but ultimately result in a couple's inability to conceive a child. Infertility is not uncommon with one in six to one in seven couples in the UK affected.

Below describes some of the reasons conceiving can be made difficult, for both males and females. However, sometimes the reason for infertility cannot be explained for an individual or a couple.

Female factors:

Infrequent ovulation or failure to ovulate

This factor represents 25% of infertility and is usually related to polycystic ovaries, which can affect how often eggs are released. It can be diagnosed through an ultrasound scan showing enlarged ovaries or small cysts and treated using medication or injections.

Blocked or damaged fallopian tubes

Fallopian tubes can be damaged leading to scarring or blockages following pelvic inflammatory disease, endometriosis or pelvic surgery. Blockages in the fallopian tubes can prevent sperm reaching the egg, and scarring can prevent mature eggs travelling down the fallopian tubes. Laparoscopy will confirm the extent of the damage and whether tubal surgery or IVF is the best treatment option.


Endometriosis is the presence of endometrium cells outside their normal location such as the pelvic walls, on the ovaries or fallopian tubes. Endometriosis will bleed at the time of a period and small cysts filled with blood can be produced, usually resulting in a painful period. As a consequence, adhesions can occur which can affect fertility and can be treated using medication, laser treatment, surgery and/or IVF.


Fibroids are very common, and are made by fibrous benign growth within the uterine wall. When they are very large they can cause infertility because they distort the uterine cavity and in these cases they can be removed using laparoscopy, hysteroscopy or open surgery.

Male factors:

Failure of sperm production

A problem with the quality of sperm is a common cause of subfertility. Men may have a low sperm count, slow moving sperm or abnormally shaped sperm. Genetics, lifestyle and certain medications can have an effect on the quality of sperm. A semen analysis can determine the quality of sperm and the necessary treatment.

Blocked vas deferens

The vas deferens are the ducts which carry sperm from the testes to the urethra. Blockages can prevent sperm appearing in ejaculation. An examination can determine if this is the case and can be treated by Microsurgical Epididymal Sperm Aspiration with IVF / ICSI treatment.