The risk of conception on different days of the menstrual cycle

Abstract Data on 1898 menstrual cycles, for 241 married women, were analysed by means of a quantal regression programme. The locations of the day of ovulation was determined by the basal body temperature method. Estimates were obtained of the risk of conception from an act of coitus on each day, as measured from the day of ovulation. The relationship between fecundability and coital frequency was also examined.