My baby is developing a flat spot on the side of his head. I have been doing tummy time and I hold him in different positions throughout the day, so how is this happening? I thought flat heads only came from babies who were never held. Could there be something wrong with my baby?
Plagiocephaly (flat head) is very common in babies, in fact, most babies have a flat head at some point or another. Even babies who do tummy time can get flat spots. I have heard of a baby that was mainly carried upright in a sling or wrap that did not develop a flat spot, but other than that most babies I have known had plagiocephaly.
Your child's sleep surface is the likely culprit. Babies spend most of their time asleep. If they are in the same position for several hours every day, then they develop flat spots. You hear this mainly from babies who sleep in swings, car seats, or other sitting devices for the night. However, the crib is not exempt here.
At this point it is important to note that cribs are the only sleep surface that is certified for infant sleep. In fact, the AAP stated in a recent article that, "there are multiple concerns about using sitting devices as a usual infant sleep location. Placing an infant in such devices can potentiate gastroesophageal reflux and positional plagiocephaly. Because they still have poor head control and often experience flexion of the head while in a sitting position, infants younger than 1 month in sitting devices might be at increased risk of upper airway obstruction and oxygen desaturation." You can find the full article here.
It sounds like you are doing things right. Tummy time and holding your baby in different positions throughout the day can help combat plagiocephaly. At your next pediatrician appointment, have your doctor look at your baby's head. They will tell you if it becomes something to worry about. You can also use the Boppy Noggin Nest Head Support to try and help. Just always provide supervision when your baby is using it and never let baby sleep on it unless you are awake and watching. It is a pillow, and thus a suffocation hazard. If it is used in the bouncy seat while baby is awake, then it should be fine.
I hope this helps!