It's also known as crib death, but many times, it may not happen in a crib at all.

Researchers have found that about one in eight cases of SIDS, or sudden infant death syndrome, may occur when babies are placed to sleep on a sofa. The study was led by Dr. Jeffrey Colvin, a pediatrician at Children’s Mercy Hospital in Kansas City, Montana. Colvin's team looked at the cases of 7,934 sudden infant deaths in 24 states, comparing those that occurred on sofas with those in cribs, bassinets or beds. They found that the risk was so high on sofas because oftentimes several safe-sleeping practices were dismissed at once.

Doctors have long-urged parents to put infants to sleep only on their backs, and on a firm, flat surface without a pillow or blanket. But the new study found that parents were more likely to lay their infants face down or tuck them in with pillows and a blanket on a couch than they would have if they had put them to sleep in a crib. 

Sadly, in most of the sofa-sleeping SIDS cases the researchers examined, they found that the parents were right there with their babies when it occurred. Colvin noted that parents may think SIDS can't happen if they are awake and watching. But whether they were exhausted — as new parents often are — and fell asleep or were simply distracted, the parents did not realize how quickly a tragedy such as SIDS could occur.

With this new research, health care providers are re-emphasizing the need to put babies to sleep on their backs in a crib without a pillow or blanket — even if it's just for a nap and even if you're right there with them.

Related on MNN:

What's the SIDS risk for sofa-sleeping babies?
Study explains the reasons why babies who aren't sleeping in a crib face a series of risks.