A 50-day-old baby can sleep flat on his back or on his side. However, if your baby does not sleep well on his/her back or is prone to breastfeeding, he/she can sleep on his/her side. A 50-day-old baby needs enough sleep to maintain growth and development, and sleeping on the side may be more comfortable and relaxing for the baby. At the same time, newborn babies are more likely to spit up and overflow milk, and sleeping on their backs can lead to choking and coughing, which can be avoided to a large extent by sleeping on their sides. Therefore, if there is a milk spillage situation can be used to sleep on the side. However, it is worth noting that the side sleep should be reasonably adjusted direction, avoid always a direction. Also, avoid sleeping prone to avoid the risk of suffocation. Newborns can sleep on their sides and flat on their backs, but you can make reasonable adjustments according to your own situation. If uncomfortable symptoms appear, go to the hospital in time to check the consultation, early detection, early improvement.