Causes

Babies have weak neck muscles and often struggle to support their heavy heads. If a baby is forcefully shaken, his or her fragile brain moves back and forth inside the skull. This causes bruising, swelling and bleeding.

Shaken baby syndrome usually occurs when a parent or caregiver severely shakes a baby or toddler due to frustration or anger — often because the child won't stop crying.

Shaken baby syndrome isn't usually caused by bouncing a child on your knee, minor falls or even rough play.