Is it safe for my baby to sleep in a swing or car seat?

What the evidence says

Car seats, swings, strollers, and infant carriers are great for their intended uses, but they aren't designed or recommended as a baby's regular sleep space. The AAP and CDC both advise against using these 'sitting devices' for routine sleep, especially for babies under 4 months.

The concern is that young babies don't yet have strong head and neck control. In a sitting or angled position, their head can flop forward and block their airway, or their body can slump into a position that makes breathing harder. This risk is highest for infants younger than 4 months.

If your baby does fall asleep in a car seat, swing, stroller, or carrier, it's fine, just move them to a firm, flat crib or bassinet as soon as you safely can. The exception is when the car seat is actually being used in the car during travel.

A CDC-reviewed study found that of thousands of sleep-related infant deaths studied over 10 years, a small percentage happened in sitting devices, most often car seats, and most of those involved the seat being used outside its intended purpose or not per instructions.