Ovarian Reserveis a term that is used to determine the capacity of a woman’s ovaries to provide eggs that are capable of fertilization resulting in a successful pregnancy.  A woman’sOvarian Reserveis the combination of her egg quantity and egg quality.

Egg Quantity:  A woman’s ovaries are her “egg bank” from which she draws during her reproductive life.  A woman has a finite amount ofOvarian Reserve.  She makes all the eggs she will ever have before they are born and usually 300,000 to 400,000 follicles by puberty.  A woman’s egg supply begins to be depleted before birth, and continues until menopause.

During a woman’s monthly menstrual cycle, approx. 20 follicles will begin their journey to become mature eggs.  However, only 1 or 2 of these eggs will mature into quality eggs ready for fertilization.

The other eggs are lost.  Thus with age, the number of eggs for a possible pregnancy declines.

Ovarian Reservetesting helps assess the number of eggs in a non-invasive way.  The most common test is a blood test which assesses the level of FSH on cycle day 3.  Such testing can tell us about the quantity of eggs a woman has, but it tells little about the quality of those eggs.

Egg Quality:The quality of a woman’s eggs is directly related to fertility and is crucial to conception.  Some of a woman’s eggs will be so-called good egg while some will not.Egg Qualityis determined by the number of chromosomes present in a given egg.  What causes poor egg quality is also often a decrease in the energy supplied by the mitochondria of an egg.  This energy is vital to ensure the growth an egg.  Insufficient energy will likely lead to a miscarriage.

Age is among one of the biggest factors affecting egg quality in a woman.Egg Quality, as well as quantity, declines significantly with age.  In her 20s or 30s, a woman will likely have a larger proportion of good eggs available for fertility.   In her late 30s and 40s, the proportion of bad eggs will likely be greater.

PoorEgg Qualitycan result in an egg not being properly implanted in the uterus even though it has been fertilized.  Eggs that are successfully implanted may not be healthy enough to survive and result in miscarriage.  Abnormal chromosomes, which are more likely to be present in older women, can result in genetic abnormalities such as Down’s syndrome.

Possible solutions for poor egg quantity or quality include IVF, using donor eggs or embryos, or adoption.  For example, an infertile female may seek donor eggs, usually up to 15 eggs (ova, oocytes), when she does not have eggs that can be successfully fertilized, often due to advanced reproductive age.  Alternatively, a female may seek donor eggs if she has early onset of menopause, or was born without ovaries.  Couples who undergo IVF with donor eggs have about a 30 to 50 percent chance of having a baby per IVF cycle.