Aside from freezing ova, embryos and blastocysts, another option is to harvest reproductive cells and tissue from the male partner. Sperm and testicular tissues can be preserved, and this service is available for men who wish to bank their sperm for the future.
Cryopreservation of sperm and testicular tissue is especially useful for men who have been diagnosed with cancer, and face treatment modalities that are potentially harmful to their reproductive organs and cells. These treatments include chemotherapy and radiotherapy. Sperm freezing gives couples the option for fertility treatments such as intrauterine insemination and in-vitro fertilization in the future. This can be of great benefit to couples, especially if current circumstances are not favorable for conception.
Patients usually come in for consult after being referred by their health care provider. The consult is typically brief: your fertility specialist can handle any questions and clarifications you and your partner care to discuss.
Sperm Freezing
The male partner is asked to submit a semen sample, which is immediately warmed and kept at 37˚C. The sample undergoes liquefaction, and is then mixed with a freezing medium that allows it to survive freezing and storage. The freezing medium contains cryoprotectants, which remove water from the cells and prevent ice crystals from forming and causing cell death.
The samples of semen are frozen in vapors of liquid nitrogen and placed in cryovials for storage until they are needed. Each sample of ejaculate yields anywhere from one to six vials of semen. The vials are labeled and catalogued for easy reference and retrieval.
The survival rate for cryopreserved sperm is highly variable, thus it is recommended that one of the cryovials be thawed to assess the success rate and viability of cryopreservation. Sperm are usually frozen for one year, however they can be frozen for longer periods if needed. Studies have shown that the likelihood of resulting in birth defects is the same for cryopreserved sperm and fresh ejaculate, and the chances of having a healthy newborn are indeed similar.
Testicular Tissue Freezing
The ability to preserve testicular tissue is important for maximizing the use of the tissue for sperm production. This treatment is of particular use to men who have cancer but still have viable testes, and wish to father their own biological children.
Testicular tissue freezing is a solution for treating azoospermia, a medical condition wherein a man has no measurable sperm in his semen. Although it is often caused by testicular abnormalities, azoospermia can be due to physical obstruction of the ejaculatory duct; in which case testicular function and sperm production are normal, and preserving this tissue is warranted.
Cryopreservation of testicular tissue can also be done for prepubertal boys undergoing cancer therapies that are toxic to their still-developing reproductive organs. Thus, it is a viable option in preventing male sterility.
After consulting with a fertility and assisted reproduction specialist, the patient undergoes screening for hormones, infection, and possibly chromosome testing. Then he is admitted for surgery, which can be performed under local or general anesthetic. A small incision is made, and a small section of testicular tissue (approximately 2-3mm) is extracted for histologic examination and freezing. The specimen is divided into several smaller sections, so that one can be tested for the presence of viable sperm. The other sections are frozen and stored in liquid nitrogen for future use, such as ICSI or in-vitro fertilization.
Here are some advantages of freezing testicular tissue:
- The surgical procedure for testicular tissue biopsy is simple.
- There is a low risk for infection and bleeding.
- Surgery can be performed several months prior to any assistive reproductive therapy procedure, at the convenience of the male partner.
- Microscopic evaluation of the tissue sample can give an accurate diagnosis for the reason behind azoospermia.
- If the biopsy specimen shows no sperm present, counseling for donor sperm or other options can be done immediately, avoiding unnecessary procedures to be done on the female partner.