Although there was no statistically significant increase in bleeding risk during menstruation, this fact may be a result of low statistical power rather than a lack of effect. Thus, the results suggest that there may be a clinically significant increase in the risk of moderate bleeding. Nevertheless, the GUSTO-I experience is consistent with the concept that the lifesaving benefit of thrombolytic therapy for acute myocardial infarction should generally not be withheld because of active menstruation.