Gamete cryopreservation is the technical name for sperm banking and is the cooling and storage of sperm at very low temperatures for a prolonged period.
Men may choose to bank sperm if there is a possibility of losing fertility. This is an important option for men who have not established a family or whose family is not yet complete.
All men who hope to father a child in the future should consider cryopreservation of semen or testicular tissue, even if the specimens have low numbers of sperm.
Semen for cryopreservation is obtained by masturbation, and must be brought to the ART (Assisted Reproductive Technology) laboratory within 1 hour of being produced. Once in the laboratory, an analysis of the quantity and quality of sperm is made and a small test vial is prepared. The remaining sample is divided into smaller amounts and transferred into multiple vials. The number of vials stored depends on the total volume of the sample, and the number of mobile sperm in each milliliter. The entire freezing process is completed in about 3 hours. The following day, the test vial is thawed, and an examination of the number and motility of the defrosted sperm is performed.
The major risk of cryopreservation is failure of the sperm cells to maintain their viability and fertility during the freezing and thawing process. In general as many as one-half of the sperm cells in a sample will not survive the process. The data obtained from the test vial will help determine how many samples of semen would best be obtained to optimize chances of successful reproduction in the future. Every semen specimen must be analyzed prior to freezing with a small amount separated into a test vial to be thawed and analyzed the next day.
The number of specimens cryopreserved will differ for each patient and depends on several factors. The patient's age and the number of children he has already fathered are both important considerations. Semen quality, partner's fertility status, and overall health will be among the factors to consider when deciding the number of specimens to have frozen.
The highest number of sperm will be found in the semen if at least 48 hours is allowed between ejaculates. If time permits, we generally recommend that at least 3 separate ejaculates be banked.
Banked cryopreserved semen can be used for reproduction in several ways. All methods will require a physician's assistance. The simplest method is Intra Uterine Insemination (IUI). During IUI, the doctor places the thawed, washed sperm within the uterus of the female partner, near the time she is ovulating. Semen quality, female fertility factors and age will affect pregnancy rates. Furthermore, the number of specimens frozen will determine how many IUI attempts can be made. According to the American Society of Reproductive Medicine, the average pregnancy requires 4-5 ovulatory cycles with IUI. More vials of frozen sperm increase the chance of a successful pregnancy, as well as the ability to attempt subsequent pregnancies.
In vitro fertilization refers to the assisted reproductive technique in which eggs are taken from a woman's ovaries and then fertilized with her partner's sperm in the laboratory. The fertilized eggs, or embryos, are then transferred into the womb and the fetus is carried in the women's uterus until birth.
Males who are unable to produce more than one sample because of health or time constraints, or whose sample may have sub-optimal levels of sperm should still be encouraged to bank semen. Newer assisted reproductive techniques, such as Intra-Cytoplasmic Sperm Injection (ICSI) make fertilization possible with only very few sperm. Similar to IVF, eggs are harvested from the female's ovaries; a single motile sperm is injected directly into the egg, greatly increasing the chances of successful fertilization. The fertilized egg is transferred into the womb and carried in the woman's uterus until birth. The field of assisted reproductive technology is expanding and changing rapidly. It is possible that research will lead to newer and even more successful options in the future.
Sperm Banking: Preparing for the Future