Causes may be mundane( eg, a neonate accustomed to the tight environment of the womb becoming frightened by unrestricted arm and leg movements) or serious( eg, ear infection, abdominal pain).

• 它有可能是日常原因引起的（习惯于子宫紧密环境的新生儿会因手足运动的自由而受到惊吓）哭闹常常无明显原因。