Male fertility preservation at a glance
- Sperm freezing, often referred to as sperm banking, is the collection and cryopreservation of a man’s sperm for future reproductive use.
- Men undergoing medical treatments that may interfere with fertility, including a vasectomy and chemotherapy or radiation for cancer, are great candidates for freezing sperm.
- Men who are deployed in the military or other occupations that keep them away from home for extended periods of time, or who are away at the time of ovulation during fertility treatment, can also bank sperm so that their partner can attempt pregnancy in their absence if desired.
- Frozen, or “banked” sperm, can be stored indefinitely until needed for assisted reproductive procedures, such as in vitro fertilization (IVF), intrauterine insemination (IUI) or sperm donation.
What is sperm freezing?
Sperm freezing involves collecting a man’s semen sample, separating the sperm, analyzing it, then freezing and storing it in liquid nitrogen. Frozen sperm samples can be thawed and used for fertility treatments or donated to other couples or individuals long after the sample was collected.
Sperm freezing has been successfully used since 1953 and can help individuals and couples to conceive healthy babies. The process is safe, standardized and continues to improve as technology advances.
Who should consider sperm freezing?
Men may choose to freeze their sperm for a variety of reasons including but not limited to their personal health, male-factor infertility diagnosis, age or having an occupation that puts them in contact with toxic materials or that could result in injury and infertility.
Often times, men will choose to preserve their sperm if they are about to undergo a medical procedure that could negatively affect their fertility. For example, men beginning cancer treatments such as chemotherapy or radiation, both known to compromise male fertility, are often encouraged to preserve their sperm.
Men might also freeze their sperm prior to a vasectomy, which enables them to avoid vasectomy reversal surgery should they choose to expand their family later. Additionally, if a man has a health condition that requires long-term use of steroid treatments, it may be advisable to freeze sperm.
Couples undergoing IVF or IUI can also use previously frozen sperm for insemination or to fertilize eggs that have been collected for IVF when the male partner is not immediately available to provide a fresh sample.
Research has shown that just as female fertility declines with ages, so does male fertility, though to a lesser degree than it does for women. If a man is concerned about his future fertility due to advanced age, sperm freezing can act as an insurance policy for the ability to grow a family later.
Men who are frequently exposed to heavy metals, radiation or toxic chemicals including pesticides might also consider preserving their sperm.
How does sperm freezing work?
The cryopreservation process begins with the gathering of ejaculated seminal fluids that contain sperm. In cases where a structural abnormality such as a varicocele is present, surgical retrieval is a likely option.
Once a semen sample is collected, it is quickly transferred to a laboratory for analysis of the quality and quantity of the specimen.
Sperm are frozen for storage using one of two methods, slow freezing or vitrification. The end goal is to cool the sperm to -196º Celsius, or about -320º Fahrenheit, the temperature at which biological processes stop. Slow freezing, the older of the two methods, freezes tissue very slowly, typically at a rate of .3º–2º Celsius per minute. The slow freezing process can take several hours to complete.
In contrast, vitrification, which is a newer process, uses cryopreservant chemicals to keep water crystals from forming within the biologic tissue and “flash freezes” the sperm instantaneously. While vitrification has significantly changed the way that eggs and embryos are frozen, sperm can be successfully and safely frozen using both methods.
Once frozen, sperm can be stored for an indefinite period. When a male patient is ready to use the frozen samples, they are carefully thawed and used in IUI or IVF.