Your baby’s risk of SIDS is much higher any time he or she sleeps on his or her side or stomach. (A baby placed on its side can roll over on its stomach.) These positions put your baby’s face in the mattress or sleeping area, which can smother your baby. So, every time you put your baby in bed to sleep -- for naps, at night, or any time -- lay your baby down on his or her back. Don’t let your baby sleep in a stroller, car seat, baby seat or swing for a prolonged period of time. Get your baby out and lay him or her on a flat surface or bed.