Fertility Preservation

Fertility preservation is the process of saving or protecting reproductive tissues and cells to allow individuals to have biological children in the future. This is particularly important for individuals undergoing medical treatments that can impair fertility, such as chemotherapy, radiation, or certain surgeries, as well as those delaying parenthood for personal, career, or social reasons.

Female Fertility Preservation

Two main options exist for female fertility preservation: oocyte (egg) freezing, and embryo freezing. Another term for freezing is “cryopreservation”.

Oocyte (Egg) Cryopreservation

This option is typically chosen by women who do not have a current partner or not interested in using donor sperm. Hormone injections are taken for approximately two weeks in order to stimulate the ovaries to produce multiple eggs. The eggs are retrieved during an out-patient minor surgical procedure and then immediately frozen in a rapid-freeze process called “vitrification”. Eggs can remain frozen for many years without a loss of viability. It may require more than one “cycle” of egg freezing to obtain an optimal number of eggs. Your reproductive endocrinologist will discuss the recommended number with you, based on a fertility calculator guidance. The ART (Assisted Reproductive Technology) calculator for egg freezing typically estimates the number of eggs a woman needs to freeze at a given age to have a certain probability (e.g., 70%, 80%, 90%) of achieving at least one live birth in the future. These calculators use statistical models based on large datasets from fertility clinics and published studies.

Embryo Cryopreservation

This option can be chosen by women who do have a male partner or are willing to use donor sperm. As with egg freezing, hormone injections are taken for approximately two weeks in order to stimulate the ovaries to produce multiple eggs. The eggs are retrieved during an out-patient minor surgical procedure, fertilized with sperm to create embryos, and then frozen for future implantation. Embryos can remain frozen for many years without a loss of viability. Embryo freezing has been available longer than egg freezing and is generally more successful in resulting in pregnancy. However, the success rates for both procedures continue to improve over time.

Timing is critically important for females diagnosed with a fertility-impacting condition. A consultation with a reproductive endocrinologist needs to be arranged as soon as possible so the delay in treatment can be kept to a minimum. Oftentimes, hormone injections can be started within days of the diagnosis. There are many financial assistance programs, for medications and procedures, available to cancer (and similar conditions) patients. REI (Reproductive Endocrinology and Infertility) physicians and their teams are uniquely positioned and experienced to assist patients navigate through this challenging time.

Ovarian Tissue Cryopreservation

This is the only option available for girls who have not yet gone through puberty, as they cannot respond to the hormones required to stimulate egg growth and maturation. It has also been used with women who cannot delay treatment for the time needed to complete and egg retrieval. The process involves removing and freezing tissue from the ovary that contains the dormant, immature eggs. When the female has completed treatment for her cancer (or other condition) and is healthy enough and ready to attempt pregnancy, the tissue is re-implanted into her body (location for implantation varies) to restore hormone function and hopefully, her fertility. Ovarian tissue freezing is only done in a limited number of clinical locations. Success is still quite limited, and it is therefore not considered a first-line option for most individuals facing potential loss of their fertility.

Male Fertility Preservation

By far, the most common procedure for males wishing to preserve their fertility is cryopreservation of sperm. Two other options exist for very specific indications: Testicular Sperm Extraction (TESE), and Testicular Tissue Cryopreservation.

Sperm Cryopreservation

Collecting and freezing sperm for future use or donation has been possible for many years – since the mid-20^th century. A sample of semen is collected through masturbation, divided into portions of about 0.5 mL each, and then frozen. Frozen semen samples can be stored for many years. When ready to be used, the samples are allowed to thaw and prepared for use with the intended procedure (IUI, IVF). Not all sperm will survive the freeze-thaw process, but since typically samples contain many millions of sperm, sufficient numbers of viable sperm are present in thawed samples to make this process very reliable and widely used.

Testicular Sperm Extraction (TESE)

This option is used for men who cannot produce a semen sample, and those who have an extremely low sperm (or zero) sperm count. In a minor, out-patient surgical procedure, sperm are extracted directly from testicular tissue. The sperm are then frozen for future use. Because the number of sperm obtained through this process will be low, future use typically involves the need for in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI).

Testicular Tissue Cryopreservation

Similar to Ovarian Tissue Cryopreservation for females, this is the only option available for prepubertal boys. However, it is still considered experimental and is not available as a mainstream therapy.

Some Special Considerations for Both Males and Females

1. Counseling and Ethical Considerations

• Fertility preservation should include discussions on ethical, legal, and psychosocial aspects, including future use, consent, and disposition of gametes or embryos in case of death or incapacity.

2. Transgender Individuals

• Transgender women (assigned male at birth) may preserve sperm before hormone therapy or gender-affirming surgery.
• Transgender men (assigned female at birth) may preserve oocytes or ovarian tissue prior to hormonal treatment or surgery.
• It is essential to discuss fertility preservation options before starting hormone therapy or undergoing surgical procedures, as these can impair or eliminate fertility potential.