Intrauterine insemination (IUI) is a procedure that involves placing concentrated, washed sperm inside a woman’s uterus to increase the number of sperm that are able to reach the egg. This increases the chance of fertilization and pregnancy.

Following intercourse, only a few hundred sperm will make their way through the cervix and out the fallopian tubes to the egg. With IUI, millions of motile sperm are flushed into the uterus and out the fallopian tubes.

IUIs are timed to coincide with the patient’s ovulation. This is usually accomplished with careful monitoring of a patient’s cycle with blood tests and ultrasounds. Often it is timed to occur 36 hours following a medication (HCG injection) that causes ovulation.

How is an IUI performed?

In this lab procedure, the sperm is first concentrated in a centrifuge, and the remainder of the semen is discarded. The drop of fluid containing the concentrated motile sperm is then loaded into a catheter, which is brought into the room to a nurse or physician.

A nurse or physician will place a speculum to visualize the cervix. Then the 1mm catheter is passed through the cervix into the uterus, and millions of motile sperm are released into the uterus and out the fallopian tubes. The IUI procedure is short and involves minimal discomfort.

When is IUI used?

IUI is almost always used in conjunction with fertility medication to improve the chances of success; in only rare situations is it used in a natural cycle. It can be used in cases of slightly decreased sperm count or motility, hostile cervical condition, sexual dysfunction, and with use of donor sperm.

It is also often used in cases of unexplained infertility, along with fertility medication, to increase the chance of fertilization.

IUI does require the sperm to reach and fertilize an egg on its own; it is therefore not appropriate in couples with very low sperm count, motility issues, or in cases of abnormal sperm morphology. IUI is also not appropriate for those with tubal disease.

How successful is IUI?

Infertile women under the age of 38 have success rates of 15-25% per cycle when IUI is used with a fertility medication. Success rates for women age 38 and older is much lower, only 5-15%.