The analysis of vaginal bleeding patterns induced by fertility regulating methods. World Health Organization Special Programme of Research, Development and Research Training in Human Reproduction.

Contraceptive methods often induce disturbances in vaginal bleeding patterns which are the main reason for women to discontinue method use. Knowledge of these changes is essential for effective counselling and product development and necessitates adequate methods of collection and analysis of vaginal bleeding data. These issues were reviewed by clinicians, medical statisticians and computer analysts during several consultations organized by the World Health Organization Special Programme of Research, Development and Research Training in Human Reproduction and their discussions are summarized in this paper. Recommendations are made on the use of menstrual diary cards for data collection. It is suggested that the analysis of menstrual patterns be based on the reference period method developed by Rodriguez et al. in 1976 to which several modifications in terminology and choice of summary statistics are proposed. While these are presented as the minimum required for the comparability of studies, other points of analysis are identified which need further study, in an attempt to stimulate research in this field by other investigators.