Variability in Menstrual Bleeding Patterns: Comparing Treated and Untreated Menstrual Cycles

Abstract

Dr. Belsey’s paper begins with two fundamental concepts. First, interindividual differences in bleeding patterns associated with steroid contraception are neither random nor erratic. I make this concept explicit because, as is true for untreated menstrual cycles, it is only the conscious negation of the notion that menstrual bleeding patterns are erratic that leads us to define the nature of variability in these patterns and to search for determinants of this variability. Although our knowledge about the exogenous and endogenous determinants of variation in menstrual bleeding patterns remains limited, sufficient evidence exists to indicate that both inter- and intra-individual variation are associated with differences in host and environmental factors.