Back to Sleep: The Best Bedtime Position for Baby

The number-one problem with back sleeping is the possibility of developing a misshapen head, from lying on the same spot on a still somewhat soft skull all the time.

Back sleeping may cause flat spots on the back of the head, which you may hear called by its fancy name, positional plagiocephaly. This is a cosmetic concern that rarely requires surgical intervention. According to Dr. Sadler, "There are no neurological problems associated with positional plagiocephaly. Development is indeed normal, and in the vast majority of cases the asymmetry resolves as the infant spends more time upright, rolls over in bed on his/her own, and spends less time sleeping. It only becomes a cosmetic issue when the molding is severe, or when the child is approaching the age of two when the growth of the head is 75 percent to 80 percent complete."

Most health insurance plans won't cover treatment for cosmetic problems like an asymmetrical head if it is not causing a health problem, so parents should be alert to this possible side effect of back sleeping, and take preventive measures.

Changes in head shape can usually be prevented or treated by alternating the head position (facing left or right) during sleep from week to week or day to day. Changing the baby's orientation to outside activity such as the door to the room often accomplishes this. Changing the placement of interesting things such as mobiles or mirrors beside the crib can also entice Baby to look the other way. Babies should also spend time on their stomachs when they are awake. In extreme cases where the asymmetry is noticeable and the baby resists measures to change head position, a pressure-distributing helmet can be used during sleep, but this has largely fallen out of favor.

Another problem that can plague parents is a baby who seems to refuse to sleep on his back. The AAP used to suggest side sleeping in such cases, which didn't seem to reduce the SIDS risk as much as back sleeping but was at least a big improvement over tummy sleeping, but since 2005 the organization has not recommended side sleeping. Dr. Sadler observes that "many, many children have slept on their stomachs and done fine." "However, any increased risk isn't worth it when it comes to a child," she says, "so I'd encourage you to keep Baby on his back—despite the wails—at least until he is well past six months old."

One remedy for both of these problems is a lot of tummy time. Time spent on her belly, holding her head up, kicking her feet, reaching for objects around her, or playing with textural parts of a play mat give Baby's head a break from pressure on the skull. They also provide mental stimulation and physical exertion, both of which should help her sleep better when her next naptime rolls around.