How do you avoid bacterial vaginosis while your on your period?

Knock on wood! I hope I don't have bacterial vaginosis which I haven't noticed any discharge at all.

How do you avoid getting bacterial vaginosis while your on your menstrual cycle since it can set off the menstrual cycle while on it?

Also which probiotic is good to taken at walmart or Walgreens? I have been to taking vh essentials and cranberry. I don't exactly know if those are real good to take and if it works the same way like other probiotics does.

I just want an probiotic or anything that will keep bacterial vaginosis away completely.