Plateau due to everyone's favorite aunt?

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Sorry if this topic has already been put to bed.

I recently went from 220lbs to 199lbs. I'm 5'9. So far I lost the weight through Jillian Michael's DVDs and watching MFP caloric limits. The last 2 weeks though, the scale hasn't budged. I kicked it up a notch workout-wise and ate the same calories, but cleaner. This morning at my weigh-in, the scale said 199.5. Seriously, wtf?? I've also been drinking about 10 glasses of water a day.

Question is....I'm getting the famous "aunt flo" for a visit any day now. I can't remember this being a factor in the previous 2 couple months, but I also weighed more then. Could this be a factor?