Okay to use pedialyte? Details inside..?

My three week old daughter seems to push and push and strain and grunt constantly, but does not poop. She sometimes cries when she does this as well. Sometimes she'll do this and poop such a tiny amount it only takes a second to clean. I explained this to her pediatric and she recommended that I give her 2 oz of Pedialyte a day to help. Is this a good idea?