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Pharmacology 17

A 32-year-old woman presents to the office with complaints of missed period for the last two months. She uses a combined oral contraceptive, which she has taken regularly with no missed doses for the past 6 years. She states that she has regular menstruation every 28 days with 4 days of moderate bleeding, but that she missed her period this month and last month. She denies any other complaints or conditions other than missed periods. Past medical history is significant only for onychomycosis treatment 6 weeks ago, treated with a prescription of oral griseofulvin for 4 months duration. Family history is significant for aortic dissection in her father at age 52 years. She does not drink alcohol, smoke cigarettes, or use illicit drugs. She runs 2 miles 3 days a week for exercise. Current medications only include griseofulvin. Vital signs are temperature 37.2° C (98.9° F), blood pressure 120/80 mm Hg, pulse 84 beats/min, respirations 16/min, and oxygen saturation 98% on room air. She is 5’7” and weighs 145 lbs (66 kg). Physical examination shows no abnormalities. Her laboratory results are:

  • Thyroid stimulating hormone (TSH) 2.0 uU/mL
  • Free T4 10 mcg/dl
  • Follicle stimulating hormone (FSH) 0.1 IU/L
  • Leutinizing hormone (LH) 0.8 IU/L
  • Prolactin 6 ng/ml
  • bHCG 250 mIU/mL

Which of the following is the most likely cause of the patients missed menstrual periods?

  • A) Adenomyosis
  • B) Anovulation
  • C) Exercise-induced amenorrhea
  • D) Griseofulvin
  • E) Pituitary adenoma


Lloyd Taylor


Dr. Ted O'Connell