How Sperm Are Prepared For IUI

sperm washing

Sperm washing is the laboratory process that is used to separate sperm from semen to be used in infertility treatments such as intrauterine insemination (IUI) and in-vitro fertilization (IVF). The goal of sperm washing is to separate healthy, motile sperm cells from less viable sperm cells.

Once the sperm have been adequately prepared for intrauterine insemination, healthy sperm are injected directly into a woman’s uterus to increase the likelihood of fertilization. It is important to note that semen is not directly injected into a woman’s uterus because it is not hygienic, and may lead to infection, uterine contractions, or other complications.

A semen sample is collected via ejaculation into a sterile cup, or through the use of a collection condom. It is very important that the semen sample reaches the lab within thirty minutes after ejaculation, so if the sample must be collected in a private setting, it must be nearby. Fertility clinics themselves are usually equipped to facilitate the collection of the sample in-house, ensuring that the sample can be processed in time.

Two laboratory techniques commonly used to process sperm include the “swim-up” layering method and the “Density Gradient Separation” method.The “swim-up” or “sperm-rise” method uses a layering technique, using special culture medium forming a layer over a small amount of semen in a test tube. As the name implies, high-quality sperm are able to “swim up” into the culture medium. After 30-90 minutes this sperm-rich medium is then centrifuged. This entire process may be repeated to allow more sperm to enter the culture medium. After the final wash, the sperm cells are ready for the IUI procedure.

In Density Gradient Separation,the recovery of healthy sperm is greatly improved, and is especially useful for sperm samples of poor quality. Using a dense liquid solution, the lighter immotile sperm and debris separate from the motile sperm, which sink to the bottom of the test tube.

The process of sperm washing can take as little as 30 minutes, up to two hours, depending on the washing technique. Insemination is performed via IUI or IVF as soon as the sample has been processed. During IUI, after sperm washing, the sperm concentrate is injected through the cervix into the uterus by means of a thin, flexible catheter. The process takes only a few minutes.Women may experience mild, temporary cramping during the process. Although they can resume their regular activities the same day, women should be aware that there is a small risk of infection from intrauterine injection. If symptoms such as fever, chills, pelvic pain or abdominal pain occur, they should contact their physician immediately.

For IUI to be successful, a sperm count of over one million washed sperm is necessary. A sperm count less than 5-10 million after washing renders pregnancy rates that are significantly lower. If the washed count is over 20-30 million, success rates are greatly improved, but above 50 million, there is no significant advantage.