Bleu, how do you know that the Boffins don't regularly stand on our doorstep making pronouncements on scientific matters??
Re: Mattress protection, I have never needed it for waters breaking as mine don't, but agree waterproof covers feel horrid. My compromise thus far has been a breathable woven artificial fibre one which is really aimed at the anti-allergy market, but it is still quite odd to sleep on, so I think I might treat myself to this.
www.thewhitecompany.com/department2.aspx?DepGrpCode=BED2&DepCode=WPRE
I'm more worried about breast milk etc after the event tbh. We bought a very nice sprung memory foam mattress recently and I want to look after it.