The topic of this blog is Fertility Preservation and it was contributed by my partner, Dr. Nicole Noyes, who helped bring successful egg freezing to NYU.

Fertility preservation is a hot topic today. The most common and successful means to preserve fertility is through egg freezing (also known as oocyte cryopreservation). More than 500 babies have been born from this technique worldwide. Egg freezing is a process whereby eggs are stimulated in the woman’s ovaries and then harvested and stored for use at a later date. This can be done in the setting of a medical emergency, such as a newly-diagnosed cancer, or for personal reasons e.g. a woman who is not in a life situation currently conducive to childbearing.

It is important to understand that egg quality is best when a woman is in her reproductive prime, meaning between the ages of 16 and 28. Most women today are not looking to mother a child in their teens and quite frankly, our society has stigmatized childbearing at the age when women are most fertile. This leaves many young people looking for ways to protect themselves against pregnancy in their early prime years and then facing the choice of when childbearing is optimum. In some instances, this decision is easy – when life events are streaming parallel with having children. In other circumstances, the decision appears arbitrary or worse, can be in direct conflict with concurrent life choices such as career and/or personal advancement and fulfillment. Many women in their 30s are struggling with the latter situation.

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 desired, it is best to have eggs that are frozen when they are of the best quality possible. For instance, eggs frozen at the age of 35 are more usable than fresh oocytes produced at 43 years of age.

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 FSH (follicle stimulating hormone). Normally, during the reproductive years, a woman’s body releases one egg from the ovary in the middle of each menstrual cycle. The fertility medication tries to cause maturation of more than the usual one egg so that multiple oocytes can be obtained from one treatment cycle. Follicle Stimulating Hormone is self-administered as a daily subcutaneous injection for about one week, during which time monitoring of the ovarian response is necessary through frequent doctor visits. The ovarian monitoring usually includes five to seven visits in the course of two weeks where blood tests and ultrasound examinations are carried out. During this time, the patient may experience some abdominal discomfort, weight gain and irritability.

Once the eggs are deemed “ready” by the doctors, a late-night shot is necessary, followed 1 ½ days later by the oocyte harvest procedure, commonly known as the “egg retrieval”. The harvest is performed under mild sedation and takes about 15 minutes to complete. 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 our clinic is 14, the range being 2 to 42. It’s important to appreciate that not all oocytes are suitable for freezing. Of the average 14 aspirated eggs, usually only two-thirds are mature and only mature eggs are currently frozen for later use. A special microscopic exam of the eggs can be performed before eggs are frozen if the lab is equipped that evaluates the spindle, the part of the woman’s egg that later serves as a platform for chromosomes to align after thawing and fertilization by a male sperm. On average, women at our program have about eight eggs retrieved that exhibit a spindle. It is important to point out that not all eggs are meant to be babies and not even all spindle-positive eggs can be guaranteed to create pregnancy. From prior data in our lab, we estimate that approximately one-quarter of mature eggs exhibiting a spindle will result in embryos suitable for transfer back to the uterus.

After the egg harvest or retrieval, a short recovery room stay is necessary. It is important to have an escort take you home after the procedure because of the anesthesia. Once removed from the body, the eggs are brought to the clinical laboratory where they are initially evaluated for health and then frozen.

Over the week following the egg retrieval, some additional abdominal bloating is experienced by most women. During this time, we advise you to refrain from high-impact exercise or long-distance travel. This discomfort usually peaks approximately one week after the procedure and then subsides completely over the following few days. This feeling is the result of the natural ovulation process; it is just more intense after treatment because multiple eggs have been extracted from the ovaries as opposed to the one usually released during natural ovulation.

At present, oocyte cryopreservation is still considered “experimental” by the American Society of Reproductive Medicine. This is in part due to the fact that many centers around the country currently offering egg freezing have never had or have a very low success rate regarding pregnancy. In addition, there have been many fewer babies born from egg freezing and thawing than from embryo freezing and thawing, or from regular fresh IVF treatment cycles. It is important to do your homework when pursuing egg freezing; you need to check out the success rates of the clinics you are considering.

Dr. Nicole Noyes

Thanks to Dr. Noyes for taking the time to write this entry. I will give a few comments on egg freezing next time.
Dr. Licciardi

References:

  • Noyes N, Knopman J, Labella P, McCaffrey C, Clark-Williams M, Grifo J. Oocyte cryopreservation outcomes including pre-cryopreservation and post-thaw meiotic spindle evaluation following slow cooling and vitrification of human oocytes. Fertil Steril. 2010 Nov; 94(6):2078-82.
  • Rudick B, Opper N, Paulson R, Bendikson K, Chung K. The status of oocyte cryopreservation in the United States. Fertil Steril. 2010 Dec; 94(7): 2642-2646.
  • Rybak EA & Lieman H. Egg freezing, procreative liberty and ICSI: the double standards confronting elective self-donation of oocytes. Fert Steril. 2009 Nov; 92(5): 1509-12.
  • Liu KE, Greenblatt EM. Oocyte cryopreservation in Canada: a survey of Canadian ART clinics. J Obstet Gynaecol Can. 2012 Mar; 34(3): 250-6.
  • Werner M, Reh A, Labella PA, Noyes N. Laboratory evaluation in oocyte cryopreservation suggests retrieved oocytes are comparable whether frozen for medical indications, deferred reproduction or oocyte donation. J Assist Reprod Genet. 2010 Nov; 27(11):613-7.