What you can expect

By Mayo Clinic Staff

Egg freezing has multiple steps — ovulation induction, egg retrieval and freezing.

Ovulation induction

At the beginning of your menstrual cycle, you'll begin treatment with synthetic hormones to stimulate your ovaries to produce multiple eggs — rather than the single egg that normally develops each month. Several different medications might be needed, including:

  • Medications for ovarian stimulation. To stimulate your ovaries, you might inject medication such as follicle-stimulating hormone (Follistim Aq, Bravelle) or human menopausal gonadotropin (Menopur).
  • Medications to prevent premature ovulation. To prevent premature ovulation, you might inject medication such as a gonadotropin-releasing hormone agonist (Lupron) or a gonadotropin-releasing hormone antagonist (Cetrotide).

During treatment, your doctor will likely use vaginal ultrasound — a procedure that uses sound waves to create an image of the inside of your ovaries — to monitor the development of fluid-filled ovarian cysts where eggs mature (follicles). Blood tests also will be used to measure your response to ovarian-stimulation medications. Estrogen levels typically increase as follicles develop and progesterone levels remain low until after ovulation.

When the follicles are ready for egg retrieval — generally after eight to 14 days — injections of HCG (Pregnyl, Ovidrel) or other medications can help the eggs mature.

Egg retrieval

Egg retrieval is done under sedation, typically in your doctor's office or a clinic. A common approach is transvaginal ultrasound aspiration. During this procedure, an ultrasound probe is inserted into your vagina to identify the follicles. A needle is then guided through the vagina and into a follicle. A suction device connected to the needle is used to remove the egg from the follicle. Multiple eggs can be removed from your follicles in about 30 minutes.

After egg retrieval, you might experience cramping. Feelings of fullness or pressure might continue for weeks because your ovaries remain enlarged.

If your ovaries aren't accessible through transvaginal ultrasound, placement of the needle might be guided through laparoscopy — a procedure in which a slender viewing instrument (laparoscope) is inserted through a tiny incision near your navel.

Freezing

Shortly after your unfertilized eggs are harvested, they're cooled to subzero temperatures to stop all biological activity and preserve them for future use. The makeup of an unfertilized egg makes it more difficult to freeze and lead to a successful pregnancy than does the makeup of a fertilized egg (embryo). As a result, your health care team might apply special techniques, including:

  • Use of cryoprotectants. These substances help prevent eggs from forming harmful intracellular ice crystals during freezing.
  • Slow-freeze method. In this method, programmable freezers are used to slowly freeze eggs and prevent them from forming intracellular ice crystals. A slow-freeze method can also be used to protect eggs from potential exposure to toxins in the cryoprotectants. In this application, low concentrations of cryoprotectants are used initially. As the temperature is gradually reduced and the eggs' metabolic rates decline, higher concentrations of cryoprotectants are used.
  • Vitrification. In this method, high initial concentrations of cryoprotectants are used in combination with cooling so rapid that intracellular ice crystals don't have time to form.

After the procedure

Typically, you can resume normal activities within a week of egg retrieval. Avoid unprotected sex to prevent unwanted pregnancy.

Contact your health care provider if you have:

  • A fever higher than 101.5 F (38.6 C)
  • Severe abdominal pain
  • Weight gain of more than 2 pounds (0.9 kg) in 24 hours
  • Heavy vaginal bleeding — filling more than two pads an hour
  • Difficulty urinating
Jan. 17, 2013