Do you mean as in, is SS harder when your on your period? I wouldn't say so, but then i've been bleeding pretty much non stop since i started SS so don't really have anything to compare it to. Plus of course everyone is different
Some people do find the cravings, etc harder around TOTM - mainly because a lot of us tend to 'comfort eat' around that time. But, other people have found it easier around that time because they are bulling through SS and food doesn't figure into things.