Leaving sleeping babies unattended in sitting positions such as in car seats, bouncers, and strollers could be dangerous for the child, a new study revealed.

At least several hundred babies die every year because of sleep-related deaths in sitting devices that have been used improperly. Most of these sleep-related deaths occurred when babies were tucked asleep in car seats while the vehicle was not moving.

"Using CSSs for sleep in non-traveling contexts may pose a risk to the infant," the study authors said in a report published by the American Academy of Pediatrics.

Here's Why Parents Shouldn't Leave Babies Asleep In Car Seats

In the new study, which has been issued in the journal Pediatrics, researchers examined data from 2004 to 2014 that contained 11,779 cases of sleep-related death in babies whose median age at death was at least 2 months old.

The research considered factors such as primary caregiver, setting, bed-sharing, objects in the environment, and other risk factors.

What the study found is that at least 3,700 babies die every year because of sleep-related deaths. At least 3 percent of these cases or approximately 348 babies died in sitting devices, which were mostly car seats. Improper use of car seats was found in 90 percent of these cases.

Majority of the sleep-related deaths in sitting devices occurred at home and under the supervision of a parent. When compared to other deaths, researchers found that babies who died in sitting devices had a health care provider or a babysitter as the primary supervisor at the time of death.

Moreover, about 75 percent of babies who died in sitting devices had at least one risk factor, while more than 50 percent had two or more risk factors.

Are Sitting Devices Hazardous Products For Babies?

Sitting devices such as car seats, bouncers, strollers, swings, and other infant seats are designed for activities such as transportation, feeding, and playing.

However, these devices can be used improperly, such as when parents rely on them as alternatives for cribs or bassinets. As a result, babies can fall from an elevated surface on which the device was placed or flipped onto a soft surface and suffocate.

Additionally, babies can also be injured or killed with improper buckling of car seat straps, the study added.

In April, more than 4 million Rock N' Play Sleepers by Fisher-Price were recalled after the deaths of 32 babies were reported by Consumer Reports. Some of the babies who died while in the sleepers suffocated because of their position while some rolled over while unrestrained.

"The main take-home message is not the combination of risk factors so much as it is (the problem of) using car seats as replacements for cribs or bassinets," said Jeffrey Colvin, one of the co-authors of the study.

What Should Parents Do To Keep Their Babies Safe?

The study's main purpose is to warn against improper use of sitting devices for sleeping babies, but it does not mean that parents should be panic when babies fall asleep in their car seat during a drive.

"But you just have to remember that car seats are for cars and when you get out of the car, the safest thing to do if your infant is still sleeping would be to put them in a bassinet or a crib," said Colvin.

The AAP recommends that babies should not be placed on an incline to sleep. The elevated head could increase risks for asphyxiation and suffocation. The straps on sitting devices could also strangle infants. What parents should do is to place their babies in a supine position for every sleep until they reach one year old. Loose bedding and soft objects must not be kept around the sleep area.