Not only is tight-hugging underwear often uncomfortable when worn for long periods of time, it’s also not the healthiest situation for your vagina because it limits airflow. And just as important as well-fitting undies are those made with the right material. “Cotton undergarments are the best due to their breathability,” explains Melissa Goist, MD, an ob/gyn at The Ohio State University Wexner Medical Center. “Synthetic fabrics tend to hold onto moisture, possibly causing skin irritation.” Though cotton is likely your gyno’s first choice in fabric, it sometimes lays lumpy and bumpy under your clothes. But fear not, there are close runner-ups. “Panties made of things like polyester, nylon, Lycra or Spandex sometimes have more stretch and lay nicer under clothing and still come with that cotton crotch,” adds Melissa Piliang, MD, a dermatologist at the Cleveland Clinic.