Doctors have found that placing babies on their backs to sleep helps prevent SIDS (sudden infant death syndrome). However, babies who lie in one position too long may develop an abnormal head shape called plagiocephaly (pley-jee-uh-sef-uh-lee), or positional molding.

What is Plagiocephaly?

Plagiocephaly means slanted or flattening of the head. An infant’s skull is very soft to allow the brain to grow during the first year of life. If the head stays in the same position, a flat spot may develop because of the baby’s soft skull. Plagiocephaly is when the side or back of the head becomes flattened, often due to lying in one position too long.

It occurs in babies who sleep on their backs or spend a big part of the day in an infant carrier and/or stroller.  The combination of sleeping on the back and pressure on the back of the baby’s head can create a flat spot.

It may also occur due to abnormal muscle tone in the muscles of the neck that control head position.  It can cause the head to turn to one side and/or tilt.  This may also cause positional molding.

Once the head changes begin, if the baby is not put in different positions, the flat spot may get worse. If your baby's head still has a flat spot at 3 months, a molding helmet may be needed to improve the flat spot. The entire head can change shape, even the face! Without treatment, changes in face shape can lead to an eye imbalance and a change in jaw shape.

  • Change your baby’s position often when awake.
  • Limit the amount of time your baby rests in baby furniture – car seats, infant carriers, and strollers.
  • It is very important to put your baby on his tummy when he is awake and being watched. This takes the pressure off the back of your baby’s head and reduces the chance to develop a flat spot.
  • Being on his tummy while you are with him will strengthen the neck, arms, and tummy and back muscles. With stronger muscles, your baby will be able to look both ways, which will help reduce the pressure to the same side of the head.
  • When your baby is awake, focus on supervised Tummy Time with your baby.



  • Children with plagiocephaly (abnormal head shape) should be referred to Plastic Surgery by 4 months of age.  
  • Torticollis (abnormal muscle tone in the neck) may be treated conservatively through Physical Therapy services and can be referred to at any time.

Last Updated 12/2015