Women are born with all the eggs their body will ever have, and no new ones are produced post the birth. An average of two million eggs are present in a woman’s body, of which nearly eleven thousand perish on a monthly basis in the pre-puberty stage. In her teenage years, a woman has around three hundred thousand to four hundred thousand eggs, although the actual count differs widely based on the size of a woman’s ‘ovarian reserve’. Of these remaining eggs, about a thousand die each month. This inexorable death of eggs every month is independent of hormone production, pregnancies, birth control medication or even health and lifestyle changes. The phenomenon continues to occur every month regardless of ovulation, stimulation or ovarian inhibition. At the point when a woman’s body exhausts its supply of eggs, her ovaries cease their production of the oestrogen hormone, and she undergoes menopause. This decline in reproductive capacity is unique to women, since male bodies continue to produce testosterone and sperm at nearly the same rate throughout their lives, barring a minor diminution with the onset of old age. There are ways by which doctors can measure the egg count at any stage of a woman’s life.
◦ The first is an antral follicle test, in which an ultrasound is used to count the visible follicles. Each follicle holds an egg that has the potential to mature and ovulate. This test, in addition to providing an accurate egg count, can also indicate how many eggs a woman can freeze in one cycle. It is most effective at the beginning of the menstrual cycle.
◦ The second is an AMH (Anti-Müllerian Hormone) test, which measures the level of AMH, a protein hormone produced inside the follicles. AMH levels can indicate the number of follicles inside the ovaries, thus giving an estimate of the total egg count. This test can be conducted at any point in the menstrual cycle, since AMH levels are mostly consistent at all times. The lower a woman’s AMH, the lower her egg count is estimated to be. Standard AMH levels for a fertile woman vary from 1.0-4.0 ng/ml, but the value can vary from this range, depending on factors like age and lifestyle habits.
Population studies have inferred that the average woman becomes infertile by her late thirties or early forties, and undergoes menopause by age fifty. The mean age of the end of female fertility is believed to precede menopause by ten to twelve years. The culmination of the fertility period for a normal, fertile woman, and the age at which menopause is attained, correlates strictly with the diminishing number of eggs in her ovaries.
Egg count, however, is not the only factor in age related decline of fertility in the female body. Another equally important fact is egg quality, which refers to the genetic state of an egg at the time it is released. As eggs are present in the body from the time of birth, their quality is affected by a host of factors over time, like fevers, toxins, infections and stress, all of which cause slight degradation in the quality of eggs over time.