The "en-caul" birth, not to be confused with the "caul" birth, occurs when the infant isΒ born inside of the entire amniotic sac. The sac balloons out at birth, with the child remaining inside of the unbroken, or partially broken membrane.
Being born with a caul is rare, occurring in fewer than 1 in 80,000 births. This statistic includes "en-caul" births, which occur more frequently than authentic caul births; therefore authentic caul births are rarer than the statistic indicates. Most "en-caul" births occur in premature births.