Dr. Nicole Noyes

Reproductive Endocrinologist
Specializing in Infertility,
In Vitro Fertilization (IVF)
and Egg Freezing

Successful Human Egg Freezing and Fertility Preservation

The fertility clinic where I work has established a successful Fertility Preservation (FP) program using a technique known as oocyte cryopreservation (egg freezing). This program is under my direction and that of Dr. Jamie Grifo. We are both full-time faculty at the NYU School of Medicine in the Department of Obstetrics and Gynecology.

Prior to 2004, only a handful of births from thawed, frozen eggs had been reported, but over the last decade, the technique has flourished. Today, more than 2,000 healthy babies have been born from oocyte freezing and thawing around the world. Importantly, the incidence of birth defects in these babies does not appear to be increased as compared to natural conceptions (Noyes et al, 2009). Still, the egg freezing techniques are exquisitely precise and have not yet been mastered by all in vitro fertilization (IVF) programs. Our clinic has been able to achieve a pregnancy rate with egg freezing similar to that of conventional IVF cycles. To date, 46% of women who have undergone an embryo transfer from frozen-thawed oocytes harvested before the age of 43 have delivered a baby or are currently carrying an ongoing pregnancy. Egg freezing is particularly useful for women of reproductive age diagnosed with a malignancy requiring chemotherapy or surgery that will render them infertile. It can also be used to extend childbearing potential for a variety of other reasons.

Egg quality is best when a woman is in her reproductive prime, meaning between the ages of 16 and 28. A women's eggs are usually still of good quality in the mid-reproductive years (meaning between the ages 29 and 38) and may remain usable (but definitely with diminished chance for producing pregnancy) in the late-reproductive period (age 39 to 44 years). If necessary or possible, it is ideal to have eggs that are frozen when they are of the best quality possible. For instance, eggs frozen at the age of 35 are superior to fresh eggs produced at 43 years of age. In addition, eggs frozen prior to chemo- or radiation therapy that is known to affect ovarian function is preferable to freezing after these treatments have been started.

An oocyte cryopreservation treatment cycles starts the same way as a regular IVF treatment cycle and involves stimulating the woman's ovaries with a fertility medication called follicle stimulating hormone (FSH). Normally, during the reproductive years, a woman's body releases one egg from the ovary near the middle of each menstrual cycle. The fertility medication stimulates maturation of more than the usual one egg so that multiple oocytes can be obtained from one treatment cycle. Follicle stimulating hormone is administered as a daily subcutaneous injection for about one week, during which time monitoring of the ovarian response is necessary (through blood tests and sonograms). Once the eggs are deemed ready by the doctor, a late-night shot is necessary, followed 1-1/2 days later by the oocyte harvest procedure, commonly known as the "egg retrieval". The harvest is performed under mild sedation and takes about 10 minutes to complete. Once removed from the body, the eggs are brought to the clinical laboratory where they are initially evaluated for health, and then frozen. The number of oocytes retrieved varies from woman to woman and may be anywhere from 0 to 45, depending on a woman's age and how the individual woman's body responds to the fertility medications.

The average number of eggs retrieved from women freezing for the purpose of deferring reproduction at the NYU Fertility Center is currently 15, the range being 2 to 55. To date, medical egg freeze cycles (e.g. those performed for cancer patients) have resulted in an average of 20 eggs retrieved (range 1 - 61) with 14 mature eggs frozen. Our center has the oldest cancer survivor worldwide to achieve live birth from frozen-thawed oocytes; she was 40.5 at the time the eggs were frozen and 43 when the eggs were thawed. Having said that, it's important to appreciate that not all oocytes are suitable for freezing. Usually only about three-quarters of eggs are mature and only mature eggs are currently frozen for later use. It is important to point out that not all eggs are meant to be babies and not even the healthiest appearing eggs can be guaranteed to create pregnancy.

Recently, the American Society of Reproductive Medicine (ASRM) lifted the experimental designation for oocyte cryopreservation in the setting of cancer treatments. At NYU, we have worked hard to establish a successful oocyte cryopreservation program and are pleased that we can offer this treatment option to women at this time.