Oocyte cryopreservation, or egg freezing, is a relatively new procedure in the field of assisted reproductive technologies. Overall, this technology increases a woman’s potential to have children later in life, especially for those who are not yet ready to start family, and who wish to become biological parent in future. Since the first successful pregnancy using egg freezing was reported in 1986, hundreds of babies have been born. Currently, pregnancy rates are around 30 percent for single embryo transfer and increases with increased number of embryo transfers up to three embryos.
Egg freezing allows a woman to preserve her fertility until she is ready to start her family. This option is available to women who are diagnosed with cancer or other illness that may affect their fertility. It is also an option for healthy women who wish to delay attempting to achieve pregnancy until later, knowing that as we age our fertility function decreases. During an egg-freezing cycle, the process of egg freezing is similar to an IVF cycle. We’ll give you medications to stimulate your ovaries to produce multiple eggs. When we consider the eggs ready for retrieval, you’ll undergo an egg collection procedure under sedation (day surgical procedure). Once we collect your eggs, we freeze them using a flash-freeze method ‘vitrification’.
When you intend to use the frozen eggs, we thaw the eggs in a reverse process in an IVF cycle without oocyte collection as you already have the eggs preserved. We then treat the eggs by using Intracytoplasmic Sperm Insemination (ICSI). This involves injecting one sperm into each viable egg. We will give you fertility medications to prepare your womb for the transfer of the embryos created using the thawed eggs. The remaining frozen eggs stay in storage.
Certain diseases or disorders require treatment that may affect fertility. For example, diseases such as cancer, genetic disorders, autoimmune diseases, can provoke infertility. If you plan to have children, you have to know how a disease or its treatment may affect fertility. Before starting treatment for any illness, you have to get information about the consequences with regards to your fertility and we also will assess your egg health and advise on their suitability.
An alternative option in fertility preservation is embryo freezing. Although egg freezing success rates are improving, we see higher success rates with embryo cryopreservation. Once the eggs are retrieved, the mature eggs are fertilized with either partner or donor sperm. These high quality embryos remain frozen until the patient is ready to use them. If patients have completed their families, they have the option to donate these frozen embryos to research, or training; the embryos can also be discarded.