As many women know, that monthly visit from "Aunt Flow" also means a good bit of water retention. This water retention can also hide any weight loss that happens just prior to your period. You actually lose weight, but those pounds are replaced simultaneously with the weight of the retained water, hence a zero loss for several days or even weeks. Then, as your period winds down, you can miraculously lose one or many pound(s). This time, as Aunt Flow left, she took 3 pounds with her, taking me from the 220 pounds I've been at for a month now to 217 pounds. The week of or after my period seems to be the only time I see any serious weight loss these days, so I sort of look forward to it!