August 2015

Your egg supply, or ovarian reserve, is the number of potential eggs that remain in your ovaries. The more eggs you have, the better your chances are of being able to conceive.
One of the strongest predictors of ovarian reserve is a woman’s age. All women are born with a finite number of eggs, typically around a few million. By the time puberty is reached the number of eggs is reduced to approximately 350,000 to 500,000. From puberty (around age 12) to menopause (around age 51+) there is a progressive depletion of egg number and quality in the ovaries, and, therefore, a decrease in ovarian reserve and reproductive potential. The rate of loss of oocytes within the ovary is genetically predetermined. Some women will experience a significant decline in the quantity of their oocytes in their forties while others may experience this much earlier. Those women who experience premature decline are considered to have diminished ovarian reserve.

How does egg development work?
In the months leading up to ovulation, the egg gathers all of the proteins, DNA and energy-producing mitochondria needed for the creation of an embryo. The egg must segregate and duplicate chromosomes over and over as they go from a single cell in the unfertilised state to an embryo composed of hundreds of cells. It requires an incredible amount of energy to create a chromosomally normal embryo. It there is not enough energy for this task, the embryo will die in the fallopian tube or fail to create a viable chromosomally normal embryo (which is usually miscarried by the 12th week of pregnancy).

What is egg quality?
We use the term egg quality to describe an egg’s ability to create a chromosomally normal embryo. As women age, egg quality declines and the rate of infertility and miscarriage increases leading to even lower live birth rates. Age is a good indicator of egg quality with live birth rates declining over age in a predictable manner for the majority of women.

What is egg count?
Women build their lifetime supply of eggs when they are babies inside their mother. Eggs are a time-limited and time-released supply: time-limited because all women will someday go through menopause, and time-released because each month only a small group of eggs gain the ability to compete to ovulate. By the time puberty is reached only 350,000 to 500,000 eggs remain. Nothing, not even pregnancy or birth control, can slow the monthly recruitment and loss of eggs. Unlike men, who reproduce new sperm every 90 days, women cannot replenish their egg supply.

I think my eggs are fine?
The only way to know if your egg supply is fine is to see a fertility specialist for ovarian reserve tests. Your monthly period is not an indicator of a good egg reserve. Most gynaecologists cannot determine your ovarian reserve either.

What is diminished ovarian reserve?
Diminished ovarian reserve refers to a clinical situation in which a woman’s ovaries do not contain as many oocytes as would be expected for her age. Ovarian reserve affects the ability to conceive and deliver a live birth.
There are other causes of diminished ovarian reserve such as the ovary having been damaged or destroyed from a disease process such as endometriosis, ovarian tumours or autoimmune issues. Other factors may include exposure to certain chemotherapy agents or radiation treatment, ovarian surgery, and pelvic infection.
It is very difficult to adequately stimulate a woman’s ovary in the presence of diminished ovarian reserve, however, superovulation can increase the chance of conception in a treatment cycle by causing more oocytes to ovulate. In some cases it can prove very difficult to stimulate the ovaries, in which case there is limited ability to increase the chance of achieving pregnancy. If the diminished ovarian reserve is so significant that a woman cannot respond to superovulation then her best option for achieving a pregnancy is through the use of donor oocytes.
While diminished ovarian reserve does not eliminate the possibility of a pregnancy, it does reveal that the woman needs to be aggressive in her quest to become pregnant as time is clearly of the essence.

What is Premature Ovarian Failure?
The average age of menopause is approximately 51 years of age. Premature ovarian failure is defined as the loss of ovarian function before age 35. Ovarian failure results from the loss of oocytes from the ovary, which leads to an inability of the ovary to produce estrogen, leading to a menopausal state. Common symptoms include the cessation of menses, and the development of hot flushes, night sweats, sleep disturbance, irritability and vaginal dryness. Hormonal tests may also show elevated FSH levels. Obviously, complete ovarian failure results in permanent infertility.
There are many causes for premature ovarian failure which can include autoimmune factors, genetic defects, endometriosis, ovarian tumours, chromosomal abnormalities such as Turner Syndrome, and cancer treatment (chemotherapy/radiation). In some cases premature ovarian failure is a result of the genetically predetermined loss of a woman’s oocytes.
Though chances are very limited, it may still be possible to fall pregnant with your own oocytes with aggressive fertility treatments. Fortunately, women with premature ovarian failure have an excellent chance of conceiving with egg donation.

When will my ovarian reserve begin to decrease?
The decline in a woman’s ovarian reserve usually beings in the early 30s and accelerates in the mid to late 30s. If your eggs are of poor quality, then they will either not fertilise, or may be chromosomally abnormal leading to a miscarriage.

Can my egg supply/ovarian reserve be tested?
At Medfem Fertility Clinic, a routine part of the infertility evaluation includes comprehensive testing for ovarian reserve to determine a treatment course and to predict the likelihood of pregnancy with any specific treatment protocol. Multiple tests are available including cycle day 2/3 hormonal FSH and AMH testing, and transvaginal ultrasound evaluations to perform an antral follicle count as well as ovarian volume testing. The FSH level should be less than 10-12 miu/ml. An FSH greater than 18 miu/ml suggests a significant reduction in ovarian reserve with a corresponding marked reduction in the chance of achieving pregnancy, even with advanced fertility treatment. Ovarian reserve may also be determined by the outcome of ovarian hyperstimulation with gonadotropin hormones.


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