What Causes Body Swelling And Weight Gain During Periods?

Hello, my daughter who is now 17 has been experiencing whole body swelling and gaining between 10-13 pounds about the time she is due for her period. The weight gain happends in about 2-3 days and can take weeks to take back off. She also has had body pain during this "puffy" time but has only had that once. She has been to SEVERAL doctors and has had SEVERAL blood tests which all but one has come back normal. The one that has come back elevated is the ANA but drs say that that test alone really doesnt mean much. She also gets very tired and depressed during this "puffy" time. We would LOVE if anyone could help us with any kind of insight as to what may be happening to body. She normally weighs about 133 when she is not puffy but goes to about 146 when this happens.