Learning About Cryopreservation for Female Fertility

Cryopreservation is a way to freeze and store reproductive tissue so that it can be used later to try to have a baby. This may include freezing eggs, embryos (fertilized eggs), or ovarian tissue. It can help protect your ability to have a biological child in the future. Frozen eggs, embryos, or tissue can be safely stored for many years.

Fast freezing is used to protect the cells while they are being frozen.

You might want to freeze your eggs or embryos for several reasons. You might be waiting to have children for personal, career, or financial reasons. This is sometimes called planned or elective egg freezing.

You might also think about it if:

• You are about to have cancer treatment. Chemotherapy and radiation can harm your eggs or ovaries.
• You have a health condition or need surgery that could affect your ovaries.
• You have a condition like endometriosis. Tissue that normally lines the uterus grows outside of it. This may lower your fertility over time.
• You are going through in vitro fertilization (IVF). In this process, eggs are fertilized outside the body. You may want to save extra embryos for future use.
• You are seeking medical or surgical gender-affirming treatments.

Fertility naturally declines with age. Freezing eggs while you are younger may give you more options later.

There are three main options:

• Egg freezing: Your eggs are collected and frozen before they are fertilized. This is a common option if you do not have a partner or do not want to use donor sperm right now.
• Embryo freezing: Eggs are collected, fertilized with sperm in a lab, and then frozen. You will need sperm from a partner or a donor.
• Ovarian tissue freezing: A small piece of ovarian tissue is removed during surgery and frozen. This may be done when there is not enough time to collect eggs, such as right before cancer treatment begins.

The process of freezing eggs or embryos usually takes 2 to 4 weeks. You will give yourself hormone injections for about 10 to 14 days. These hormones help your ovaries produce more eggs than usual in one cycle. During this time, you will have blood tests. You'll also have ultrasounds, which use sound waves to create images. This allows a doctor to check how the eggs are growing.

When the eggs are ready, a doctor collects them using a thin needle guided by ultrasound. You are given medicine to relax or sleep during this step. Collected eggs are either frozen the same day or fertilized with sperm and grown in a lab for 5 to 7 days before being frozen as embryos.

As with any procedure, there are some risks. The hormone medicines can cause the ovaries to swell. This is called ovarian hyperstimulation syndrome (OHSS). Other side effects may include bloating, cramping, mild pain, mood changes, headaches, or hot flashes.

There is also a small chance of bleeding or infection from egg collection. The process also can be emotionally stressful. It's important to know that the freezing process does not guarantee a future pregnancy.

Age at the time of freezing is the most important factor in success. Eggs frozen before age 35 tend to survive the thawing process best. They are more likely to lead to a successful pregnancy. Not all frozen eggs will survive thawing, become fertilized, or result in a pregnancy. Freezing a larger number of eggs may improve your chances.