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Fertility Preservation at PFC

Fertility preservation reduces the risk of declining fertility potential that accompanies advancing age. A young woman in her 20s and 30s can save her vital and abundant eggs, making them available for conception later in life.

Pacific Fertility Center is a leading provider of fertility preservation services to an international audience. Our experience has resulted in high success rates.

Here’s a little about our fertility preservation program and why it’s so valuable for women.

How Age Affects Your Fertility

Fertility is optimal when a woman is young and declines with age. Peak fertility occurs from ages 20 through 30. By age 32, a woman's fertility has fallen by 10 percent, and then steadily declines through the following years. Fertility is low after the 38th birthday, and successful natural conceptions are unusual after age 44.

Egg numbers decline.

At least part of the decline in conception comes from the decline in the number of eggs as you age.

• At birth, a woman averages one million eggs.
• Before puberty begins, that number declines by two-thirds to roughly 300,000 at age 13.
• At age 40, a few thousand eggs remain.
• At menopause, averaging age 50, only a few eggs remain in the ovaries.

Egg quality declines

Egg quality is a measure of the potential for each egg to produce a child. A high quality egg produces an embryo with normal chromosomes, known as a euploid (“YOO-ploid”) embryo.

Chromosomes carry the DNA that codes for the essential building blocks of life. There are 23 pairs of chromosomes, one from your mother and one from your father, along with the X and Y determining sex, in a euploid embryo. An extra or missing chromosome is found in an aneuploid embryo, one without the normal 23 pairs. Abnormal chromosomes in the embryo (aneuploid embryos) become more common as you age.

Aneuploid embryos produce a broad spectrum of clinical effects, from infertility, to miscarriage, to clinical aneuploidies, like Down Syndrome. Most aneuploid embryos stop growing shortly after fertilization, never producing a positive pregnancy test. Some produce a pregnancy, but result in miscarriage. Less often, aneuploid embryos result in viable pregnancies, but these often produce babies with significant birth defects such as Down syndrome.

So both egg number and egg quality decline as a woman ages, reducing the chance for pregnancy and increasing the risk of pregnancy complications.

Fertility preservation can help many women lower the risks of these age-related declines in fertility.

The Fertility Preservation Technique

What’s involved in fertility preservation?

Stimulating the ovaries.

First, we use fertility medications to stimulate the ovaries and produce multiple egg sacs (follicles), each containing an egg. Using a needle, a physician retrieves the eggs under ultrasound guidance and intravenous (IV) sedation. Embryologists in the lab identify the eggs under the microscope and store them, using an advanced type of “freezing” called vitrification.

Freezing the eggs.

Success rates with egg freezing depend on the number of eggs frozen and the woman’s age when the eggs are frozen. To significantly reduce the risk of future age-related fertility problems, Pacific Fertility Center recommends vitrifying:

• 12 eggs for women under age 35
• 12 to 20 eggs for women age 35 to 39
• 20+ eggs for women 40 and older

Although there doesn’t appear to be a limit to how long eggs can stay frozen, we recommend using them within 10 years of vitrification.

In vitro fertilization.

Once a woman decides to become pregnant, eggs are warmed, and inseminated, and the rest of the in vitro fertilization (IVF) process continues. Typically, about 6 eggs are warmed and mixed with sperm (inseminated). With previously frozen eggs, intracytoplasmic sperm injection (ICSI) is the preferred insemination technique. That’s because the covering over the egg (zona pellucida) hardens with freezing. With ICSI, we inject a single sperm into the egg using a small needle. Two-thirds of the warmed eggs fertilize after ICSI.

The physician transfers the best of the embryos created from that group of eggs. We usually transfer one or, at most, two embryos at a time. Other available embryos can be vitrified for future use. Chromosome screening can be performed on fertilized eggs to assure a healthy embryo is transferred.

Fertility Preservation Success Rates

Fertility preservation reduces the known risks associated with delaying conception. However, it does not guarantee a future pregnancy. That's especially true because fertility preservation cannot prevent uterine, endometrial, sperm, or technical problems that can also interfere with conception.

Published data now show excellent egg survival, pregnancy, and delivery rates, as well as normal early development for children conceived from frozen eggs.

Egg survival rates

Egg survival rates are high after vitrification. Experienced fertility programs have egg-warming survival rates of 80 to 90 percent, meaning that 8 to 9 out of every 10 eggs vitrified are available after warming for further use.

Around this average rate, however, there is significant variability between patients in egg survival.

Pregnancy rates

Pregnancy rates from vitrified-warmed eggs are indistinguishable from those of fresh eggs, according to a randomized prospective trial[1] of 600 recipients of donated eggs. Fertilization, embryo cleavage, and development through day 5 (the blastocyst stage) are essentially identical for fresh and frozen eggs. Safety and efficacy of egg freezing appear good in early studies.

A more recent follow-up study in the same clinic[2] showed a clinical pregnancy rate of 55 percent per transfer and an ongoing or delivered rate per transfer of 45 percent for intended parents of vitrified eggs from donors.

Pregnancy rates are highly dependent on age. Younger women produce more eggs and eggs of higher quality than do older women. We see pregnancy rates of over 50 percent per transfer in women under 30 and 25 to 35 percent per transfer in women in their mid-30s. We have achieved pregnancies in the 38 and older age groups, but there is little data to judge outcomes in women 38 and older. Since the number of patients receiving transfers remains limited, we cannot yet quote overall delivered pregnancy rates in this age group.

Early childhood development studies show that children conceived after egg freezing are indistinguishable from those conceived with fresh eggs[3]. Certainly more study is warranted, but childhood outcomes are reassuring.

Overall, the news is quite good, making fertility preservation an option to consider in planning your reproductive life.

[1] Cobo A et al. Use of cryo-banked oocytes in an ovum donation program: a prospective, randomized, controlled, clinical trial, Human Reproduction. 2010, 25(9):2239–2246.
[2] Cobo A et al. Six years' experience in ovum donation using vitrified oocytes: report of cumulative outcomes, impact of storage time, and development of a predictive model for oocyte survival rate. Fertility and Sterility, 2015, In Press.
[3] Cobo A et al. Obstetric and perinatal outcome of babies born from vitrified oocytes, Fertility and Sterility. 2014. 102(4):1006–1015.

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