Dear Doctor: We have always been careful to put our son to sleep on his back to prevent SIDS, but he has recently started turning over by himself, and we find him on his stomach. Should we prevent this? Should we put him on his back again?

Dear Reader: You’re right that placing infants on their backs to sleep greatly reduces the rate of Sudden Infant Death Syndrome (SIDS), the leading cause of death in infants between 1 month and 1 year old. About 1,500 infants die of SIDS each year in the United States, with most of the cases occurring in babies younger than 6 months old.

The good news is that once your baby is able to turn over by himself, which happens at about 6 months, his brain is developed enough to alert him to breathing problems. Rolling over is an important part of his development, and he should be allowed to do so.

You should continue to place him on his back when you put him down to sleep, but according to guidelines published by the National Institutes of Health, you don’t need to return him to his back when he turns over. At that point, it’s OK to let your baby choose his sleep position.

You should also:

— Be sure to use a firm mattress with a fitted sheet.

— Keep his crib clear of soft objects like pillows, stuffed toys, crib bumpers or loose bedding.

— Overheating may play a role in SIDS, so keep his room at a comfortable temperature and don’t overdress him for bed. He may be too warm if his chest feels hot or if he is sweating.

— Don’t cover him with loose bedding such as a blanket, quilt or sheet, as he may get tangled up.

— Do keep your baby close by in your room, but don’t sleep with him in your bed. The risk of accidentally rolling over on the baby or of him falling out of the bed is too great.

Follow these simple precautions to give your baby the safest sleep environment. And congratulations on your son’s milestone of turning over by himself!

Eve Glazier, M.D., MBA, is an internist and assistant professor of medicine at UCLA Health. Elizabeth Ko, M.D., is an internist and primary care physician at UCLA Health.