You will find some men to be really squeamish about blood, so the merest hint of it on a condom will freak them out. If they are prolific reviewers, they will mention the fact you're working through your period. Obviously don't let this deter you, some men are incredibly infantile and ignorant when it comes to menstruation.
I know that when I used to menstruate, I tasted a lot more metallic. While I was happy to have sex with boyfriends during my period, I would never have do so with a paying a client. But, many do work through their period, so it is up to you to find a way that suits you/your clients.
Another option is to not work during (the heaviest part of) your period, or else offer a limited service of oral (on him) and hand relief.