I have a three week old and soon after we brought him home we were worried that he may have a fever (anxiety ridden first time mom!) so we took his temp and he was fine. A couple of days later my sister was holding him and though he peed on her - realized he is just a warm blooded little boy. We have all of these thick sleepers for him, but he is too warm for them - cotton sleeping gowns are best for him. There have been a couple of times we did realize he had peed also - hard to tell sometimes! I think we are starting to master getting the diaper on snug enough on top. Good luck and congrats!