This is a link to a good, very brief article on fertility published in the Huffington Post:
… and a comment I posted in response to a reader’s question about whether or not taking the pill (or any form of contraception that suppresses ovulation) preserves fertility:
That is a good question. It makes intuitive sense that if you prevent the ovaries from ovulating by using the pill/ring/patch/depo/implant (all work by preventing ovulation) you can preserve or extend their reproductive life. Unfortunately, that is not the case. The ovaries and the follicles (eggs) they contain age right along with the rest of the body, regardless of whether or not you use the pill, etc. Just the same way the number of pregnancies you have does not affect when you become infertile (ovaries are quiescent during pregnancy as well). Taking the pill does have other important health advantages though, such as reducing one’s risk of developing ovarian or uterine cancer, and, of course, preventing undesired pregnancy.