Water births are a popular alternative to giving birth in air because many mothers find the feeling of being submerged in hot water means they experience less pain during contractions and the birth itself.
Babies born underwater are often calmer than those born in air, and tend to struggle and cry less after leaving the mother, according to guidance from public health body NCT.
Water births work because the breathing reflex is triggered by the change in temperature as the baby is born and the sensation of air on the skin.
This means that, provided the baby remains fully submerged in warm water, they continue receiving oxygen through the umbilical cord until they surface meaning they do not drown.
While there is no clear statistical evidence that babies born in water receive heath benefits, that means the opposite is also true – that there are no clear negative effects either.
However, water births are usually not recommended for mothers who have suffered complications during their pregnancy because the baby may need to be monitored with sensitive electronic equipment that cannot go in the pool.
Water births are also not recommended for very overweight mothers who may struggle to get out of the pool should their birthing plan need to change quickly.
If undertaking a home water birth, efforts should be taken to keep the water below 37C. A higher temperature risks overheating the baby and causing undue stress.
While lower temperatures are not recommended, this is largely because it negates many of the benefits to the mother – such as increased comfort – rather than because it could harm the child.