The facts on water births
Research suggests water birth leads to a shorter, less painful labour.
The water keeps women buoyant so they can change position during labour.
Many women say water births give more control and are more "spiritual".
A new study showed one in three women having a water birth did not need gas or air.
Water births first became popular as an alternative to traditional methods in the US during the Eighties.
The most recent figures suggest 20,000 of 800,000 annual births took place with the help of water.
