It is estimated only one in 80,000 babies are born still inside the amniotic sac.

This incredible footage captured that rare moment in Spain as the baby was born with the membrane stretched around its whole body.

The video, taken on Saturday, shows the baby being born minutes after its twin received a normal delivery.

The newborn lies on a hospital table moving inside the clear sac, which is known as a caul.

Fluid surrounds the baby as it tries to break free, and the blue umbilical cord can be seen trailing across its head.

Doctors and nurses gather around the table to witness the once-in-a-lifetime opportunity.