Polycystic Ovary Syndrome/Disease (PCOS/D) is a medical condition in people with vulva where the hormonal imbalance in the body causes abnormal or irregular periods among other symptoms.
Sources:
https://www.mayoclinic.org/diseases-conditions/pcos/diagnosis-treatment/drc-20353443
https://www.webmd.com/women/what-is-pcos
https://www.healthline.com/health/polycystic-ovary-disease
https://www.hopkinsmedicine.org/health/conditions-and-diseases/polycystic-ovary-syndrome-pcos