Freezing Sperm

Freezing sperm overview

• Sperm cryopreservation (sperm freezing or sperm vitrification) is the process of freezing a man’s sperm and storing it for later use, either in artificial insemination or in vitro fertilization (IVF)
• Men may choose to freeze their sperm prior to undergoing vasectomy, male-to-female gender reassignment surgery or cancer treatments. In the latter case, the chemotherapeutic drugs could harm the sperm.
• Men may also freeze sperm if they will engage in risky activity, such as going to a warzone, where he may suffer an injury that damages his fertility.
• Sperm freezing is a safe and relatively inexpensive way for a man to preserve his fertility.

What is freezing sperm?

Sperm cryopreservation (freezing) involves:

• A man providing a semen sample
• The lab analyzing the sperm for adequacy
• The lab freezing the sperm for later use

When a man decides to preserve his sperm, he can typically provide a sample by ejaculating via masturbation into a sterile sample cup. If no sperm are present in the semen or he cannot bring himself to ejaculation, a surgical sperm extraction may be used to remove sperm directly from the testicle.

The sperm sample is then frozen by a slow-cooling method or by vitrification, a flash-freezing process in which sperm are bathed in a cryoprotectant and quickly frozen to about minus 320 degrees Fahrenheit. The frozen sperm is stored at a fertility clinic or sperm bank until it is ready to be used for intrauterine insemination (IUI) or IVF.

Thawing frozen sperm: Liquid nitrogen crystals dissolve away to a gas state, unlike ice melting into water. This animation was obtained using low magnification phase contrast microscopy.

Cryopreservation provides longevity for an indefinite amount of time. Once sperm is frozen, all biological activity stops, preventing cell growth or death.

Sperm is typically frozen for long periods. The man can choose to keep his sperm frozen, use the sperm or discard the sperm. The typical yearly cost to store frozen sperm is $220-500.

Risks of freezing sperm

Sperm cryopreservation is a safe and standardized process. Since sperm was first frozen and used to create a pregnancy in 1953, cryopreservation techniques have steadily improved.

Not all sperm will survive the freezing and thawing process. However, typically millions of sperm are released in each sample, so the chances of having enough healthy sperm for IUI or intro-cytoplasmic sperm injection (ICSI) IVF are favorable.

The amount of time sperm can remain frozen and still result in the fertilization of an egg is unknown. Actual cryopreservation is considered to have no time limit.