Glasgow girl is quite right about this one. They maybe designed for couples to prevent pregnancy but in realitiy in the punting world a sponge is often used by the girls when they are on their period. Most are not willing to miss out on a weeks pay.
It very common for parlour girls to use a contraceptive sponge to soak up the menstural blood during the period.
Splitting hairs maybe but glasgowgirl's post stated that sponges are not used for birth control when clearly Anth's post showed that they can be. The statement was not clearly limited to pro$$ies.
In addition, as I mentioned, it's speculation regarding this particular pro$$ies use of the sponge. It may be because she's on her period, it may be because she wants to use it as a form of contraception. It may be both. We don't know.
It was already mentioned that pro$$ies use them for when they're on the period and I thought Anth's post was interesting. It didn't need to be argued with just for argument's sake.
Regardless, they're pretty unattractive and I would suggest all women avoid them!