A womans' age and its influence on fertility
One of the highest contributing factors of increased infertility is the fact that many couples and individual women are increasingly delaying their wish to have children. But why does fertility decrease with age? The answer to this is mainly to do with the woman's body. Every woman is born with all the eggs she'll ever have already present in her ovaries. Not only does this supply diminish over the years, but the quality of the remaining eggs becomes less optimal too. In men, whose sperm cells are in constant renewal and production throughout their lives, this problem although present to a certain degree, is less pronounced.
More specifically, the quality of a woman's eggs diminishes due to the following factors:
Somehow, the fertility of a woman is not totally dependent on the function of the ovaries. This is displayed in the following statistics: in the western world, the menopause (identified by the absence of menstruation for a period of one year), occurs around the age of 51. However, at the age of 38 (well before the menopause), 20% of women are already infertile. At the age of 42, its around 50% and at 45yrs, 90%. |
- the occurence of ovulation can reduce. The older the woman is, the higher the chances of an abnormal cycle, even if she still menstruates.
- the egg cells show more abnormalities. This increases the risk of having a child with chromosomal defects. At the age of 25, the chances of this are 1 in 500. at 35yrs, 1 in 250 and at 45yrs, 1 in 25.
- embryos resulting from poor quality egg cells do not implant well.
- the chance of miscarriage increases greatly after the age of 37. This is also due to the fall in egg quality.