The birthing center I had my water birth at had very strict cleaning and disinfecting procedures. Cleaning the tub after birth, from start to finish, took 3 hours. The birthing center also had swabs done, and was tested (by an independent lab) for germs and microbes. Any patient could ask to see the test results. In a tub that clean, the only germs you really have to worry about passing to your baby are your own. But birth is messy regardless of where the baby is delivered, and germs will be passed on anyway.
I recommend asking the birthing center what their cleaning procedures are, and if they ever have the tubs swabbed.
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