When your plans of becoming a parent are threatened, either through age or a medical condition, egg freezing may be able to help. This assisted reproduction technique allows your eggs to be collected and cryopreserved for the future.
There are several stages to the egg freezing process. These include reducing the body’s own hormones, stimulating the ovaries to produce multiple oocytes, and collecting and freezing the oocytes.
Preparing the body
Each month, your body goes through a delicate interplay of hormones which ready the uterus for pregnancy and lead to ovulation, or the release of an egg. The pituitary gland in the brain is one of the key parts of this reproductive system. For more read Ovulation Calendar & Calculator.
During egg freezing, natural pituitary hormones could cause an early ovulation before the eggs can be collected. To prevent this, medications are used to reduce the body’s own pituitary hormones. There are several methods to do this. Depending on the protocol used, it can involve taking injections or pills during the menstrual cycle prior to egg freezing, or at the start of the egg freezing cycle.
Stimulating multiple eggs
The next stage is ovarian stimulation. The ovaries contain many small follicles, each of which has an immature egg. Every menstrual cycle, several follicles grow and mature, until one or two become dominant. Ovarian stimulation uses medications to grow multiple follicles at the same time. The most common method is injections of gonadotropin, which are similar to hormones from the pituitary hormone gland. Sometimes oral medications such as clomiphene citrate (Clomid) or letrozole (Femara) are also used. Common side effects of ovarian stimulation include nausea, abdominal bloating or discomfort, and headache. More rarely, it can cause ovarian hyperstimulation syndrome (OHSS), in which the ovaries respond too strongly to the medication. Your doctor will monitor how the ovaries respond to the medication to prevent and manage OHSS or other complications.
Ultrasound is used to view the size of the growing ovarian follicles. This procedure involves a technician either moving a handheld probe across the abdomen, or inserting an ultrasound wand into the vagina. You may need to go to the clinic every day or every other day for an ultrasound. When the follicles reach the right size, a trigger injection is used. This hormone causes the follicles to release their oocytes.
Collecting and freezing the eggs
The egg collection is scheduled for one to two days after the trigger injection. Light sedation is used to prevent pain. Then, a needle is inserted through the abdomen or the vagina to the area around the ovary. Gentle suction is used to collect the eggs.
The final stage is freezing the oocytes. They are placed into a solution with chemicals which protect them from damage due to freezing. Then the eggs are very rapidly cooled to prevent ice crystals from forming. This rapid freezing process is known as vitrification.
Once the oocytes are vitrified, they are stored at very cold temperatures using liquid nitrogen. Your eggs can be stored for years, until you are ready to become pregnant. For more information read How Much Does Egg Freezing Cost?.