1) NO! They can be very dangers
2) NO! You don’t need one.
To address the dangers. Many people have tried placing a water bed heater under their inflatable water birth pool in an attempt to help keep the water warm. Seems like a logical idea.
While attending a couple midwifery conferences, I have heard first hand from several midwives that after doing this, and after the birth they discovered that the pool material had actually thinned where the heater was.
This was alarming. So… please, do not use a water bed heater under your birth pool.
To address my second point, that you don’t need one… Inflatable birth pools hold water temperature better then hard structured tubs or foam structured tubs. The thick air walls on inflatable pools are perfect insulation.
Your pool should maintain water temperature for roughly 5 hours before starting to cool down.
Start with a bit warmer water then you desire – say 100 degrees. This little bit extra temperature will help to warm the pool material without cooling the water too much.
What should you do if your pool water does cool too much? Simply add a couple tea kettle or soup pots of hot water – very carefully – to your pool. Have someone “stir” the water while you add the water slowly to the pool water being careful to not let the hot water touch the sides of the pool or the mother.
Another point about pool water cooling down. Many midwives are not rigidly maintaining pool water to a specific temperature anymore. As the mother labor advances and she gets hotter, cooler water can feel great and help keep her cool.
Babies have seem to do just fine in cooler water. Placing them on mom’s very hot chest immediately after birth will keep them warm. If a baby is not staying pink, it is easy enough to remove the baby from the water to warm and pink up. You can then warm the pool water and if all is well, give baby back to mom to relax in the warmed water.