Daytime Naps

How long should a 9 week old be napping? How many naps should they be taking? My little one was napping really well a couple weeks ago and now she will only sleep 20 minutes to an hour. My husband thinks I am doing something wrong. I follow the same routine that I do in the evening except I don't give her a bath. The room is dark, she is swaddled and white noise is going.