Hello! I’m currently 6 1/2 months pregnant and researching all about how to keep my little one safe during bedtime. I’m really confused about the use of waterproof mattress protectors and whether they’re linked to the increased risk of SIDS. Could you give some information on if the two are related? I’ve read online that a waterproof mattress protector is important to prevent bacteria and mold growing from baby liquid explosions... but I also read that if the baby rolls over onto their tummy that they won’t be able to breathe as waterproof = non-breathable. What do you suggest? Or do you have any brands that you think are safest to use. I just want my baby to be safe. Thank you for your time.

Red Nose has the following information about waterproof mattress protectors.
....always make sure that the waterproof mattress protector is strong and a tight fit.
Never put soft bedding under the bottom sheet, such as a sheepskin, as this makes the sleeping surface too soft.
A pillow, cushion or sofa is not a safe mattress as they are too soft and increase the risk of sudden unexpected infant death.
https://rednose.org.au/article/what-is-a-safe-mattress

It is very normal for baby to learn to roll safely between 4 - 6 months (some earlier/some later) Most babies then prefer to sleep on their tummy.
The firmness of the mattress is important, as baby may be at risk of suffocation if they roll & sleep on a soft surface.
https://rednose.org.au/article/what-do-we-do-now-that-a-baby-has-started-to-roll-over

Red Nose does not recommend any particular brand of mattress or mattress protector.
It is important that the mattress is firm, clean, well-fitting & flat.

My understanding in relation to breathability, is that it helps prevent mould by dispersing any fluid on mattress or protector.