If you don't mind some leaking at first I guess you don't HAVE to....but the washing removes the natural oils on fibers making them more absorbant. It's also why you want to wash natural fibers seperate the first few times, so those oils don't get on your microfiber inserts and cause them to repel.
BFP #1 11/28/09 ~ EDD 8/6/10 ~ DS Born 8/9/10 BFP #2 8/27/13 ~ EDD 5/8/14 ~ Natural MC 9/18/13 at 6 weeks, 6 days BFP#3 3/28/14 ~ EDD 12/7/14 ~ DD Born 11/21/14 BFP#4 6/15/17 ~ EDD 2/20/18
Re: Prepping?
BFP #1 11/28/09 ~ EDD 8/6/10 ~ DS Born 8/9/10
BFP #2 8/27/13 ~ EDD 5/8/14 ~ Natural MC 9/18/13 at 6 weeks, 6 days
BFP#3 3/28/14 ~ EDD 12/7/14 ~ DD Born 11/21/14
BFP#4 6/15/17 ~ EDD 2/20/18