If you've had sudden pain under your right ribs in your 40s, it may be perimenopause. Falling estrogen pushes more cholesterol into your bile, raising gallstone and gallbladder-attack risk. Cathy breaks down the estrogen-bile research, why HRT and rapid weight loss add risk, what a real attack feels like, and the small habits — steady weight, a little fat, more fiber — evidence actually supports. Sourced from PLOS ONE, Hepatology, JAMA, and NIDDK.