VIDEO : Chrissy Teigen Starts Trend Involving Photos of Babies with Head-Shaping Helmets

(CNN)American model Chrissy Teigen sparked a social media trend after sharing on Twitter and Instagram a photo of her son, Miles, with a corrective helmet to treat his flat head syndrome. The 6-month-old was fitted for the helmet to fix his "adorable slightly misshapen head," Teigen posted. my baby bug got his head shaping helmet today! please don't feel bad for him if you see photos. he is a happy bug and we're just fixing his flat! A post shared by chrissy teigen (@chrissyteigen) on Dec 3, 2018 at 5:08pm PST Flat head syndrome, or plagiocephaly, is a common problem for babies -- one in every five is affected -- because they spend a lot of time sleeping on their backs, the UK's National Health Service says.