Intra-Uterine Insemination (IUI) is a relatively simple procedure in which sperm are washed, concentrated and prepared in the laboratory to ensure that the best sperm are collected. The sperm are then injected directly into the uterus, using a fine catheter, at the time of ovulation. This treatment relies on the natural ability of the sperm to reach and fertilise the egg. The aim of IUI is to increase the number of sperm that reach the fallopian tubes and thus increase the chances of fertilisation.

Depending on the reasons for infertility, IUI can be coordinated with the normal menstrual cycle or on a medicated cycle (with fertility drugs) to stimulate the ovaries to develop several eggs and so increase the chances of a successful pregnancy. This treatment can be performed with sperm of the male partner or with donor sperm.

IUI is a widely used treatment option because it is a minimally invasive and a lower-cost alternative to in vitro fertilization (IVF).

The procedure can be used for many kinds of fertility problems, including in cases of:

• Mild male factor infertility – where there is below-average sperm concentration (low sperm count), weak movement (motility) of sperm, or abnormalities in sperm size and shape (morphology). IUI can overcome these problems by screening the sperm to separate highly motile and normal sperm from those of lower quality.
• Use of donor sperm. For women who need to use donor sperm, IUI is most commonly used to achieve pregnancy. Frozen donor sperm specimens are obtained from certified labs and thawed before the IUI procedure.
• Cervical factor infertility. The cervix may prevent sperm from reaching the egg. This may be due to the the production of overly thick mucus by the cervix which obstructs the sperm’s journey, or scarring (such as that caused by a biopsy or other procedures) which can cause the cervix to thicken. IUI is able to bypass the cervix, depositing sperm directly into the uterus and therefore increase the number of sperm available to meet the egg.
• Semen allergy and other immunological related abnormalities.

Unlike IVF or ICSI, IUI does not involve egg collection or general anaesthesia and is currently a popular and successful treatment for specific infertility problems. Success rates vary, but when the problem is related to the ability of the sperm to meet the egg, IUI can be the optimal solution. If IUI is unsuccessful after several attempts IVF or ICSI may be recommended because of a possible underlying or unidentified problem.