IUI and Sperm Washing

Artificial Insemination

Intrauterine insemination (IUI) is a type of artificial insemination (AI) used in assisted reproduction therapies (ART) to help couples who want to conceive. In the case of vaginal artificial insemination, semen is usually placed in the vagina by way of a needleless syringe. In order to get the semen deeper into the vagina, a longer tube, known as a tom cat, may be used. After insertion of the semen, the woman lies still for about 30 minutes or more to prevent seepage of the semen and to allow fertilization to take place.

An alternate method to the needleless syringe or a catheter is the cervical cap, also known as a conception device or conception cap. The cap is filled with the donor semen (or the partner's semen) and it is placed inside the vagina close to the entrance of the cervix for a period of several hours. This device allows a woman to continue about her life while the cervical cap holds the semen in the vagina. The advantage to this method is that fresh, non-liquefied semen can be used.


IUI is a type of AI; however, it is done using the sperm only rather than semen, which includes sperm and seminal fluid. This method is more efficient than artificial insemination because the sperm is injected directly into the woman's uterus, bypassing the vagina entirely. In order to effectively use this method of insemination, it is critical that the semen is washed so that only the sperm are injected into the uterus. Seminal fluid contains prostaglandins and, if injected directly into the uterus they cause muscular contractions (as happens in menstrual cramping). The pain and cramping caused by these hormones can be very painful and can cause uterine collapse along with other complications.


Although sperm washing has been associated almost exclusively with IUI and assisted reproduction, in recent years it has branched out to be included as part of HIV treatment in a preventative way.

Since HIV/AIDS first became an epidemic, some 30 years ago, it was a given that children born to HIV positive women were at extremely high risk for contracting the disease. If the father was HIV positive, then both mother and baby were put at risk. Since the epidemic has slowly been coming under control, the number of children infected with HIV dropped to a low of 141 in the US as of 2005. This number is one-tenth of the number of children infected when HIV was at its peak in the mid-1990s. By early detection, many women with HIV infection were able to receive appropriate treatment and other interventions during pregnancy, labor, and delivery to spare both mother and child. The combined treatments reduced the risk of transmission from 25% down to less than 2%.

Now, with the effective medicines and treatments available to help people with HIV live relatively normal lives with near-normal life expectancies, the idea of having a family is a realistic possibility - as it is for any couple. Serodiscordant couples (one person is HIV positive and the other is HIV negative) face certain challenges but with the help of special programs of assisted reproduction, they too can conceive safely and have a family. However, IUI for serodiscordant couples is only designed for couples where the male is HIV positive and the female is HIV negative.

Sperm Washing

In order to accomplish IUI with serodiscordant couples, sperm washing is necessary. This procedure reduces the risk of HIV transmission to the female partner and protects the baby. Although there may be a small risk of transmission, recent studies indicate that in 1,000 live births to serodiscordant couples, all babies born were free of HIV and the mothers were not infected either.

Sperm washing concentrates and separates the sperm from the infectious seminal fluid through a special process. In some sperm banks, a trial wash is done to help determine what type of sperm washing would yield the best results. In the basic wash, a sperm wash solution containing antibiotics and protein supplements is added to the ejaculate. After repeated centrifugation, the seminal fluid is eliminated from the sample and the sperm cells are concentrated for insemination. This process takes between 20 and 40 minutes.

A more intense wash separates the sperm and uses density gradient centrifugation to isolate and purify the motile sperm for a sperm sample with motility of at least 90%. The process starts out with a semen sample set on top of a layer of Isolate then centrifuged. Debris, round cells, non-motile and poor quality sperm remain on the top layers and only the motile sperm are able to get through to the bottom layer. The sperm is concentrated for use for AI. This process takes about an hour.

Depending upon the quality of the sperm sample, the swim-up method of sperm washing can yield concentrated sperm with a motility of at least 90%. A layer of fresh media is gently added to the semen sample in a way that most of the motile sperm will swim out of the sample and upward into the added media. The harvested sperm are then used in IUI. A man with low sperm, sperm that has low motility or male infertility will not be able to use this method.

For the couple dealing with HIV, there now is hope for conception and birth. Learn more about IUI and sperm washing here.

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