Women are born with all the eggs they will ever have. While we are born with over a million eggs, by puberty just 300,000 are left. From this huge number of eggs, only 300 will ever become mature and be released in the process known as ovulation.
In women, fertility declines more quickly with age. This decline becomes rapid after the age of 35. This has a number of causes, but particularly the decline in the quality of the eggs released by the ovaries.
Way before menopause begins, our bodies’ reproductive capabilities slow down, becoming less effective at producing mature, healthy eggs. As you age and come closer to menopause, your ovaries respond less well to the hormones that are responsible for helping the eggs ovulate.
This natural decline of fertility happens in the healthiest of women, though bad health habits, like smoking, have been shown to speed up the decline of fertility.
Most oocytes will fertilize when they are placed in a culture dish with several thousand normal sperm. This process is called “in vitro fertilization” or “IVF.” When there are not enough normal functioning sperm for IVF, fertilization will usually occur after a single live sperm is injected into each egg, termed “intracytoplasmic sperm injection” or “ICSI.” But still, on rare cases, fertilization does not occur even with ICSI, presumably because of a problem inherent to either oocytes or sperm. If this happens, the use of donor sperm cells or donor oocytes will usually result in fertilization.
-Infertility is a medical condition that is found in both men and women, and men and women are affected almost equally.
-With men, declining sperm counts, testicular abnormalities, and decreased reach of climax are common causes of infertility. With women, the most common causes are tubal blockage, endometriosis, PCOS, and advanced maternal age which affects egg quality/quantity.
If more than one embryo is implanted in your uterus, IVF can result in a multiple pregnancy — which poses health risks for you and your babies. In some cases, fetal (embryo) reduction can be used to help a woman deliver fewer babies with lower health risks. Pursuing fetal (embryo) reduction, however, is a major decision with ethical, emotional and psychological consequences.