First and foremost, ask your ob/gyn. Only a medical professional who works with pregnancy and pregnant women will have the right answer for you!
Secondly, a healthy body and spirit is a healthy place for a baby to grow. I cannot see how exercise while you're trying to conceive will affect your chances, but, again, I'm no medical professional.
However, make sure you're working closely with your healthcare provider so that once you are pregnant, you don't do anything to jeapordize the health of your fetus.