My SD Moms Thanks to the “Back to Sleep” campaign launched in 1994, just about everyone’s heard that babies should be placed to sleep on their back. And for good reason: 
numerous studies have shown that this lowers the risk of Sudden Infant Death Syndrome (SIDS), which may occur when baby is on his stomach and can’t breathe well with his face against the mattress. Yet some parents may find themselves in a pickle when their baby makes it abundantly clear that he hates sleeping on his back and seems to prefer going to sleep on his stomach or side instead.
First off, know that you’re hardly the only one struggling with this problem. “Many infants do not like to sleep on their backs,” says Dr. Deena Blanchard, MD, a pediatrician at Premier Pediatrics NY. The reason: “This position is easier to startle in, and infants with reflux who spit up may feel less comfortable on their backs. Most babies do sleep better on their stomach.”
Yet that doesn’t mean you should indulge your baby’s preference. “The risk of putting an infant to sleep on their stomach is not worth it,” Dr. Blanchard continues. Even though your baby may sleep better in this position, that’s exactly what might be boosting the odds that something could go wrong.