Mrs Thomas is 30 years old and attends the GP surgery with her husband as they have been struggling to conceive for 18 months. She admits her periods are irregular and roughly has her cycle every 6 -8 weeks. There is no intermenstrual, postcoital bleeding or abdominal pain. Past medical history includes Acne and Asthma. She had a pelvic ultrasound privately one year ago due to fertility concerns which was normal. Her mother had ovarian cancer.
What is the most likely diagnosis?