There’s a microscopic ecosystem inside your intestinal tract that’s made up of trillions of bacteria, viruses, fungi and other microorganisms, and scientists are just beginning to understand its enormous impact on both your physical and mental health.

Polycystic ovary syndrome (PCOS) affects as many as five million women in the United States. This common hormonal condition occurs when small, fluid-filled sacs — called cysts — form on the ovaries.