J.P.
My son did this when he was a baby, but his twin sister didn't. Their pediatrician was not concerned at all. She said it was common. Sometimes it was a grunting sound and sometimes it sounded like a noise that sheep make.... baa... baa. He's eight years old now.... and he sleeps quietly:) I can't tell you exactly when it stopped, but it was before his first birthday. Once our ped. said it was normal, I felt relieved and could actually smile when I heard the sounds... especially when he would say... baa.... baa... Enjoy your little one! Oh... they grow up so quickly!