It is very common for women’s breasts to change in size during the month in line with her hormones and menstrual cycle. Sports Bras Direct recommends you buy a larger cup size for that particular time of the month. You may also need some different sized Sports Bras if your weight often fluctuates with either weight gain or loss. It is important to wear the correct size so that your breasts are adequately supported and the bra is comfortable. If you have one breast that is bigger than the other you will need to choose a size that fits the larger breast. Some women who suffer from breast tenderness also find that wirefree Sports Bras are more comfortable. So if your bra size fluctuates and for more information about fitting please visit our Fitting Room.