I think a little stress is normal and even healthy, but I did just write a paper on how maternal stress can influence the baby's development. Here's one study......http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0039791.
Katie - Married to Mike 06/02/01, Mom to Sydney Anne born 11/21/09 and Alice Maeryn & Oliver Thomas born 04/24/13
I agree that worrying about stress is not beneficial, but it actually helps me to de-stress knowing that it is important for my child's health. Even more reason to take time for myself and unwind