Sperm Washing

Last Updated: May 5, 2018

Definition - What does Sperm Washing mean?

Sperm washing is the process of separating individual sperm from semen. This process of sperm preparation is intended to mimic the natural process that occurs when healthy sperm separate from other elements in the ejaculate as they actively move through the cervical mucus and towards the fallopian tubes during spontaneous conception.

It is generally considered a standard component for individuals undergoing intrauterine insemination (IUI) or in vitro fertilization (IVF).

FertilitySmarts explains Sperm Washing

The procedure increases the chances of a successful pregnancy by removing dead or low functioning sperm and highlighting the strongest and most mobile specimens.

To begin the sperm washing process, a lab collects a semen sample provided by a male through masturbation. The lab then runs one of four methods.

  1. Simple wash method - used when semen is optimal, a centrifuge is used to separate sperm from other elements in the semen. This is an ideal method for intrauterine insemination (IUI) because there is generally a high yield of sperm from this technique.
  2. Swim-up, one of the most common techniques used where semen prepared in a centrifuge is layered at the bottom of the round bottom tube that contains a sperm wash medium. The tube is then placed at a 45° angle for a short period of time. The most active and motile sperm move into the sperm wash medium and can be removed.
  3. Migration-sedimentation - similar to swim-up, but allows natural settling of sperm to be used for cases where sperm have low motility.
  4. Density gradient sperm wash - separates cells based on density. Uses a similar centrifuge process, healthy and less optimal sperm have different densities. The strongest sperm separate, filtering out dead sperm, blood cells, and other debris found in semen.
  5. Swim down technique - utilizes a method that forces the sperm to swim through a progressively less concentrated solution and the strongest sperm are collected from the bottom of the sample after a period of incubation.

Sperm washing has been proven successful in reducing the chances of HIV transmission in the case of an HIV-positive male. As the HIV virus lives within the semen, not within the sperm, sperm washing allows for biological conception while reducing risk to the female partner and child. While this procedure does not eliminate the risk for HIV transmission, the medical community widely considers it a safe approach to conception.

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