Over the past 30 years, the number of women participating in organized sports 
has grown dramatically. Several forms of menstrual irregularities have been 
described in the female athlete: primary and secondary amenorrhoea, 
oligomenorrhoea, short luteal phases and anovulation. The incidence of menstrual 
irregularities is much higher in activities where a thin body is required for 
better performance. The hormonal pattern seen in these athletes is a 
hypothalamic amenorrhoea profile. There appears to be a decrease in 
gonadotrophin-releasing hormone (GnRH) pulses from the hypothalamus, which in 
turn decreases the pulsatile secretion of luteinizing hormone (LH) and 
follicle-stimulating hormone (FSH) and shuts down stimulation of ovary. 
Recently, another type of amenorrhoea has been described in swimmers which is 
characterized by mild hyperandrogenism. Athletes with low weight are at risk of 
developing the female athletic triad, which includes amenorrhoea, osteoporosis 
and disordered eating. Athletes with this triad are susceptible to stress 
fractures. Other issues include the pregnant athlete. Intensive exercise during 
pregnancy can cause bradycardia. Safe limits of aerobic exercise in pregnancy 
depend on previous exercise habits. Infertility, which may develop with 
exercise, is probably reversible with reduction of exercise or weight gain. High 
impact sports activities may produce urinary incontinence. Oestrogen replacement 
therapy is often prescribed in amenorrhoeic athletes, but bone loss may not be 
completely reversible.