Can babies harm themselves by crying?
Tropes (a concerned grandparent)
According to Penelope Leach, yes.
My Google-fu is weak atm, however. That’s all I was able to find regarding ‘crying injuries’.
ACM (a grandparent alarmist)
When my sister was a baby she used to cry so hard that she’d pass out. Seriously, she regularly exhaled with such effort and extent that she fell over unconscious and woke up seconds later - somewhat calmed and bewildered, but apparently none the worse for wear.
I always consider it a way for a baby to exercise. They squirm and cry. They can’t run and jump. I think it’s good for them as long as they are not crying out of an unfulfilled need or direct pain.
Leach has no data for this at all. I would not rank it high on the list of things to be concerned about. This is not to say one should ignore all crying, but making a leap from “crying releases cortisol and too much cortisol is bad” to “babies can harm themselves by crying” is a stretch.
Almost anything is “potentially damaging” (Leach’s phrase) so I think you have to sorta rank your issues against data.