Symptoms & care · 7 minute read
PCOS and menstrual cycles
Why PCOS may affect ovulation and cycle timing, what tracking can reveal, and why diagnosis needs clinical evaluation.
Evidence-informed · Editorial review August 2026 · Links to trusted sources are available in the interactive app
PCOS can disrupt ovulation
Polycystic ovary syndrome is a hormonal and metabolic condition. Some people with PCOS ovulate infrequently or unpredictably, which can cause long or skipped cycles and make calendar fertility estimates less reliable.
Symptoms differ between people
Possible features include irregular periods, excess facial or body hair, acne, scalp hair thinning, difficulty becoming pregnant, or insulin resistance. Having one symptom does not establish PCOS.
Tracking supports a medical conversation
Cycle dates, bleeding, symptoms, medications, and test results can help a clinician. Diagnosis may involve medical history, examination, laboratory testing, or imaging while ruling out other explanations.