Oligomenorrhea

Abnormally infrequent menstrual bleeding, typically characterized by menstrual cycles longer than the normal range (>35 days), with reduced frequency and often decreased volume of endometrial shedding. Possible causes are PCOS, hormonal contraceptives, extreme endurance training, psychological stress, low body weight, hyperthyroidism, hypothyroidism, elevated prolactin levels, diabetes, Cushing's syndrome, or pelvic infections.