Many factors are responsible for this outcome. We address each of these six primary factors below. In women less than 35 years of age, approximately 4 out of every 5 eggs that are produced are healthy and have the potential to be fertilized. The most rapid decline in egg quality occurs after the age of 40 years. Because egg quality declines dramatically with age, it is common to transfer a greater number of embryos to the uterus of an older woman in the hope of offsetting embryo quality problems.
Older women are more resistant to stimulation with fertility medications.
For this reason, women over the age of 40 commonly experience abnormal ovulation. Additionally, this is one of the main reasons that it is more difficult for older women to conceive naturally. When the ovaries of older women develop increasing resistance to fertility hormones, it is much more difficult for the woman to produce multiple follicles . The levels of FSH and E2 help to determine the most ideal dosage and regimen of fertility drugs necessary to achieve an optimal response. An optimal response will result in the production of the maximum number of follicles containing eggs in the ovary.