Stomach sleeping for infants is not good even if they have flat heads

A reader asks:

I have a 6 month old nephew whose head is very flat in the back. His mother has been informed that she can start putting him to sleep on his tummy, but I wonder if more needs to be done. She doesn’t have income or private health insurance and takes the baby to a public clinic for his exams. What can I suggest for her to do?

The flat head you describe is called plagiocephaly. Many babies get a flattened area on the backs of their heads due to a couple of factors. One is a condition called torticollis where the neck muscle called the sternocleidomastoid is slightly shorter on one side than the other due to positioning in the uterus. Because the muscle is shorter, it pulls the head to the side just a little giving a baby the look that her face is cocked to one side and some babies always want to look in one direction as a result. Because of this muscle imbalance, the baby holds her head in a position so that only one part of the back of the head is laid on. As a result that area gets a bit flat. Usually there is some compensatory protrusion on the face so that if you look at the top of the baby’s head, the shape is like a parallelogram.

The other cause of a flat area on the head, especially if the area is flat dead center on the back of the head, is laying for long stretches, asserting pressure on this area.

Whether plagiocephaly is caused just by laying on your back to sleep or is caused by torticollis (or both) having your baby sleep on her stomach to compensate is not a good plan. Although stomach sleeping would help by taking the pressure off that area and allow the brain growth happening to fill it back out, the risk of Sudden Infant Death Syndrome (SIDS) is much greater when babies sleep on their stomachs and the risk of that just isn’t worth it.

Instead, having your baby in an upright position with no pressure on the head when awake by using things like a bumbo seat and baby carrier on your chest or back for the majority of the time your baby is awake makes more sense. In addition, tummy time is really important from the very earliest weeks of life to help prevent and remediate plagiocephaly. All infants should spend time on their stomachs while awake to strengthen the neck muscles, stretch them in different directions and to decrease the amount of time they spend laying on their heads.

For some babies with torticollis, home stretching exercises and formal physical therapy can help stretch out the shorter muscle encouraging more balanced head holding and movement which will allow the head to sit in more than one position and so it won’t appear as flat in one area.

Molding helmets have also been used for some infants with extreme flat areas but data suggest that the cosmetic outcomes compared to those who don’t use helmets are not that different. It makes sense to talk with your pediatrician about the options for managing a baby with a flat spot but I would caution against stomach sleeping as a strategy.