Having just bought Mama TENS machine I was surprised to find out that the pads that come with the machine are 'single use only'. Does anyone know if this means that I can't detach and reattach the pads in the course of labour (if I, for example, want to hop in the bath or have a shower and then continue using the machine afterwards)? Replacement pads are very expensive so don't want to buy them unless I have to.