The . The use of a birth control does not directly affect your future fertility. Obviously your chance of getting pregnant while on the pill is markedly decreased. If you have trouble getting pregnant when you get off birth control, it is because of other factors. The reason why i say that it does not directly affect your future fertility is because there is one indirect way it does affect your future fertility. It affects your future fertility by allowing you to postpone attempts at pregnancy to later in your life. If you postpone pregnancy too long, your chances of getting pregnant will be lower because you are older. Your chance of getting pregnant stays the same until about 35 years of age. It then starts dropping so that at the age of 39, it is half of what it was. The moral to this story is to have a reproductive plan that is realistic. If you want to have four kids, waiting until you are 35 to start is probably not the best idea. Hope this helps!