Fertility and Age


Age is another area important in fertility.  Older women have a more difficult time becoming pregnant. Women are born with a certain number of eggs. Over time, the number of eggs she has decreases as well as their quality. So when you are younger it is much easier to become pregnant compared to when you are older. This is solely due to the quality of the egg. Some tests can help predict “Ovarian Reserve.” These tests are an indirect measurement of how your eggs are doing in your ovaries. Many studies have found that a drop in pregnancy rates occurs at approximately 35 years of age and drops dramatically after 37 years of age. The quality of the oocytes drops dramatically as age increases. The number of genetically abnormal eggs increases as age increases:

Age_fertility
This increase in abnormal oocytes leads to an increase in embryos with an abnormal number of chromosomes. Chromosomes are where our genetic material is stored. We each are composed of cells possessing 23 pairs of chromosomes. One set comes from the sperm and one set comes from the eggs. The architecture inside the egg at fertilization must bring these pairs of chromosomes together just right.  As we get older the archictcture inside the cell becomes older and sometimes does not align these chromosomes with as much accuracy as it did when the eggs were younger, resulting in an increase in the number of embryos that have what is called “Aneuploidy” or an irregular number of chromosomes. The most famous form of aneuploidy is Down’s Syndrome which is a normal complement of chromosomes, 23 pairs plus an additional number 21 chromosome, called Trisomy 21, or 3 copies of the number 21 chromosome.  Aneuploidy also decreases the rate of implantation of embryos reducing fertility rates as well as increasing miscarriage rates.

Graph_chromosome_abnormalities


Loading...