Some wear Spanx or something similar, which is basically a girdle. You can tell sometimes. Like when a woman is stuffed like a sausage in a tight fitting dress and can’t move easily, good chance she has Spanx on from under breasts right down to her panty line or even thighs. Sometimes it might be like a skort, or down to the ankles under slacks. Most women don’t wear them though. Not in America anyway.