Female Reproduction Pathophysiology
A 19-year-old history student, CV, presented to her university health centre requesting oral contraception. The GP noticed that she appeared very thin and enquired about her menstrual history. CV explained that her periods started when she was 15 and although she had regular cycles for about 1 year, during her time in the 6th form they had become very intermittent and had finally stopped altogether when she was 17. She was conscious of her appearance and liked being thin. She had started running for exercise during her schooldays and generally ran 10 miles four or five times a week and went to the gym several times weekly. On examination her body mass index was 16.5 kg/m2. She had normal secondary sexual characteristics and there were no other abnormal physical findings. Biochemistry showed LH 1.2 U/L, FSH 0.9 U/L, estradiol 54 nmol/L and prolactin 235 mU/L. A diagnosis of hypothalamic amenorrhoea associated with low weight and excessive exercise was made. After discussion she agreed to try and gain weight and 1 year later her body mass index was 20.5 kg/m2 and her periods had resumed.