This is the incredible moment a new-born baby arrived still inside its amniotic sac, completely intact.

The tiny infant can be seen moving and stretching still inside the sac, as medics prepare to snip the new born free.

The amniotic sac is a thin but durable membrane filled with fluid which helps keep a baby warm and safe from bumps during pregnancy.

When it breaks, this is typically referred to as a woman's 'waters breaking' shortly before she gives birth.

But in rare cases, less than 1-in-80,000 births, the baby is delivered with the membranes still intact and this is known as a 'caul birth'.

Some babies are born with part of the membrane still attached to them, but to be born completely encased in the intact membrane is incredibly rare.

The incredible footage shows the youngster completely cocooned in the amniotic sac (
Facebook / Gih Flor de Lis)

Many people still believe the phenomenon to be a good omen for the child's infancy and it is has even been suggested, but not proven, that caul babies will always have a natural affinity for water.

A year ago, baby Silas Philips made headlines when he was born still inside his amniotic sac .

The baby can be seen moving and wriggling around as though still inside the womb (
Facebook / Gih Flor de Lis)

Three months prematur e, Silas was still attached to the umbilical cord and able to get oxygen from the placenta.

An incredible photo captures his tiny hands pressed up against the thin membrane, CBS in Los Angeles reported.