It's a newborn, still in the sac. Giving birth with the amniotic sac intact is called a "veiled birth." It is very rare but it is possible. It is less painful because the water cushions the baby's head, meaning less bruising for both of you. Don't worry about the baby drowning, he or she will not take a first breath until he/she hits the air for the first time, and the placenta will continue to provide oxygen until that happens...
SOURCE: [interestingfunfacts]
