The number of healthy (chromosomally normal) eggs you produce declines as you get older, especially after the age of 36. The number of eggs available to go through the maturing process may be even lower if you have a family history of premature menopause, or need to undergo chemotherapy or radiotherapy.
As you get older, chromosomal errors occur more frequently in your eggs, resulting in more abnormal embryos that may not implant, or that result in early pregnancy loss.
Women can help protect their fertility from the natural ageing process by leading a healthy lifestyle. It is important not to smoke, to avoid alcohol and caffeine intake, to have a regular exercise regimen , and maintain a healthy weight range.
Due to the aging process, there is only so much that can be done, and the most important factor is to have a baby at an early age whenever possible.