Introduction

Abnormal genital tract bleeding is common, and results in significant emotional, physical, and financial pressures. 20% of women develop abnormal bleeding during their lifetimes: uterine bleeding accounts for 25% of gynecologic operations. Normal menstrual bleeding is cyclic, occurs at regular intervals of 21-45 (mean 28) days, continues for 2-8 days, and 30-80 ml of blood is lost per cycle. Quantification of the amount of blood lost can be difficult. Tampon or pad counts can be used, but are unreliable because of differences in absorbency and the frequency with which they are changed. Pre- and post- menstrual hematocrits may provide the most accurate assessment: a drop of 3 or more percentage points indicates excessive bleeding.