To understand whether babies really “cry” in the womb, it’s important to take into account what goes into the behavior of crying
not just the characteristic sound. Babies can’t be heard crying until they’re in contact with air rather than fluid, so scientists rely on studying the complex physical behaviors and responses that cause a cry.
In 2005 New Zealand researchers conducted one of the most influential studiesTrusted Source on babies crying in the womb
providing an ultrasound video of what they interpreted to be a crying baby. They broke the cry down into multiple steps, or a series of body motions and breathing (rather than just sound) to confirm that the baby was crying.
Before this study, only four behavioral, fetal states had been proven to exist, including quiet, active, sleep, and awake states.
The babies observed crying in the womb were 24 weeks and older.