Share 'Pregnant while training for strenuous physical activity?'

Are there any runners out there? I signed up for a marathon in the fall, but I was hoping to get pregnant before then. Is it a bad idea to get pregnant in the middle of training? Or, once I finish the marathon, how long will it most likely take for my fertility to return to normal (as I have heard that training might affect things)? I'm pretty young and also healthy, although I am just starting m…