Age is the most important factor affecting a woman's fertility. A woman's eggs also gradually decline in quality and quantity as she ages. A woman in her mid-20s has a 30% chance of conceiving each month at 25. Fertility usually begins to decline when a woman is in her 30s and drops more sharply after age 35. By age 40, the chance of conceiving in any given monthly cycle is about 5%. In this article, we will provide useful information about a chart that shows the effect of age on fertility in women.