O varian cysts, which are small fluid-filled sacs that develop in or on the ovaries, are very common and are usually harmless. In fact, “the process of ovulation—maturing an egg and releasing it—basically makes at least a little cyst, which pops when the egg is released, and then these cysts resolve,” explains Dr. Mary Jane Minkin, an ob-gyn at Yale Medicine. These are often called “functional cysts,” and they usually go away on their own.   Advertisement Advertisement Other types of ovarian