Egg quality decline is the most important cause of age-related infertility. Egg quality refers to the ability of the egg to create a chromosomally normal embryo. Each egg has 46 chromosomes, 23 from each parent. In order for the egg to prepare for fertilization, it must discard 23 chromosomes in order to make room for the 23 chromosomes brought by the sperm. Failure to correctly discard 23 chromosomes leads to a an embryo with the wrong number of chromosomes, medically referred to as aneuploidy.
There is no test for egg quality, but we know it to be closely correlated to age. For example women in their 20’s have a 20% chance of having a live birth with each month of timed intercourse, a rate that drops
Because the underlying cause of most miscarriages is chromosomal abnormalities, the various therapies and techniques typically promoted for prevention are not proven and are unlikely to be useful. This includes over the counter, herbal, and alternative treatments.
Occasionally, a patient is diagnosed with a medical condition that may cause or contribute to recurrent miscarriage. Treatment or correction of the underlying disease, deficiency, or abnormality may reduce the chance of future miscarriage for some patients.
A high percentage of fertile women who have unprotected sex will experience loss of a pregnancy at some point. According to the American Society for Reproductive Medicine, 25% of recognized pregnancies end in miscarriage.
The total number of miscarriages (including cases where the woman is unaware of the pregnancy) is estimated at about 50%. Pregnancy losses occurring within the first 8 weeks are most common. Few women experience miscarriage after the 12th week.