I'll give you a few tips, although im not female ha ha. This will all be based if it is not fat but purely water issue.
Water weight is usually one of two things hormones or food. Assuming it's not a hormone imbalance then food related. Few things you can do:
1) Sodium reduction (salt) cut out/reduce salt from your diet or high salt foods.
2) Drink more water (Body will naturally retain water but lack of water will cause the body to retain).
3) Mild diuretics (Vit c dosed at 2-4g per day ideally tab with each meal) also try dandelion root. If something stronger I'd opt for something like MHP Xpel. Caffeine is good for helping you to try out but I wouldn't go crazy with it.
Exercise isn't to much of an issue assuming that it IS purely water retention. Few other things you can do before a shoot such as carb loading and depletion and water loading and depletion but it's pretty complicated so aim for what I listed above and see how you get on first .