A new study, published online in Pediatrics today, has found that preventing Sudden Infant Death Syndrome (SIDS) isn't as simple as laying a baby on his or her back to sleep. While that remains the most surefire way doctors know of to reduce the risk, SIDS can still occur even if a baby has been tucked in correctly. Sadly, some babies may be predisposed to SIDS regardless of their sleeping positions. The study highlights the other major factors that could increase the likelihood of a baby dying from SIDS. Some of them are wholly preventable, such as subpar prenatal care or exposure to tobacco smoke before birth. On the other hand, researchers noted that babies born prematurely or with preexisting abnormalities in their brains were at a greater risk as well. There is good news here: Looking at larger trends over the past few decades, the study notes that infant deaths, whether due to SIDS or in general, have decreased dramatically. The research done here is a major step toward demystifying SIDS, which remains a missing link in understanding what causes babies to die so soon after birth. As we wait to learn more, doctors encourage parents to maintain a regimen of responsible prenatal care as well as safe infant sleeping conditions (babies should sleep on their backs, on a not-too-soft bed) for optimal health.