Getting pregnant before first cycle?

Alexa • My husband and I have been married since May 2014. We are the proud parents of Levi Peyton born July 5, 2016! We are waiting for our baby girl’s, Ivy Alexandria, arrival April 30!
Hey what's the reason that the doctors recommend waiting at least one cycle before trying to conceive? I want to start trying right after we hit 2 weeks from my D&C! Any advice anything?