Sperm Washing

Sperm washing is required prior to intrauterine insemination to remove chemicals and other materials that may cause adverse reactions in the uterus. It also enhances the fertilizing capacity of the sperm. Thus it is recommended in cases of immunologic, male-factor or unexplained infertility.

Sperm washing involves removing the seminal plasma and any cryoprotectant prior to intrauterine insemination. In general a choice of three techniques may be used for washing, depending on the quality of the sperm.

Basic Sperm Wash

This technique uses dilution and centrifugation. A sperm wash solution containing antibiotics and protein supplements is added to the ejaculate. After repeated centrifugation, the sperm cells are concentrated and the seminal fluid eliminated from the sample. This procedure takes 20 to 40 minutes.

Premium Wash

This method uses a two-layer density gradient medium designed to separate the motile fraction of sperm (those sperm capable of self-propulsion) from seminal fluid. The lighter medium is layered over the heavier one in a sterile test tube. A semen sample is placed over the upper layer and centrifuged. Miscellaneous debris, cellular contaminants, non-motile and poor quantity sperm remain in the upper layer. Only motile sperm are able to swim through the lower layer thus are concentrated for use in artificial insemination. This procedure takes about one hour. It may be used for fresh or frozen semen, and can help assess male-factor infertility.

Swim-Up Wash

This technique uses sperm self-migration to obtain a sample in which at least 90% are motile, depending on the initial quality of the sample. The semen sample is mixed with a sperm washing medium so that the most motile sperm swim out of the pellet and concentrate in the medium. These harvested motile sperm are subsequently used for insemination. This procedure takes about two hours.

Note that oligozoospermic men (men with low sperm counts) with poorly motile sperm, as well as men with male-factor infertility, are not suitable candidates for the swim-up technique. Their sperm will have difficulty swimming up out of the pellet into the nutrient medium.

Prior to intrauterine insemination therapy a trial on a single specimen, using all three washing techniques listed above, helps determine the one which will yield the best results.

Under normal conditions a washed specimen can be safely kept for up to two hours prior to insemination. If insemination is delayed laboratories are able to maintain the washed specimen in a special medium for 6 hours.

Sexual abstinence of at least 2 days but not more than 5 days is recommended prior to collecting a specimen.

Allergies to antibiotics should be reported prior to washing.