Infertility is defined as the inability to achieve a pregnancy after 12 months of unprotected intercourse around the time of ovulation. Infertility is a very common problem that affects about 15% of couples.

Generally, 85% of couples will conceive within the first 12 months of unprotected intercourse and another 10% will achieve a pregnancy after a further year.

Cumulative birth rates per age.jpg

Throughout the western world there has been a progressive increase in the average age of women having their first baby. The above figures are significantly affected by advancing female age with a steady decline in fertility potential after the age of 35, and a steep fall in pregnancy rates after the age of 40.


Conception is a complex process which requires many steps to happen at the right time to achieve pregnancy.

Essentially the main causes of infertility are associated with:

  • Eggs: disorders of ovulation, including polycystic ovarian syndrome (PCOS).
  • Fallopian tubes: problems occur when a blockage in the tubes prevents the sperm coming in contact with the egg.
  • Uterus: problems that interfere with the normal implantation of the embryo in the uterus (womb).
  • Sperm: a problem that arises when there are insufficient sperm with good forward movement. They also need to have the ability to fertilise the egg.
  • Endometriosis: a condition that can lead to infertility and pelvic pain.

In a significant proportion of cases (perhaps 10-15%) no cause can be found. This does not mean that the couple is not experiencing infertility, only that the tests have been unable to pinpoint the cause. This situation is known as ‘unexplained’ or idiopathic infertility.