I am looking for suggestions to help my four month old take longer naps. She will only sleep for 40 mins max(sometimes shorter). I know she is still tired when she wakes up, but she will not go back to sleep and is then tired an hour later. She sleeps fairly well at night- bed around 8pm and up around 7am with one feeding around 2 or 3am.
I have tried darkening her room, a story and rocking routine, letting her fall asleep on her own, letting her fall asleep with me and then putting her down. Nothing seems to matter.
Any suggestions would be greatly appreciated.