Variations in breast physiology due to hormonal fluctuations during the menstrual cycle can correlate to quantitative changes in Diffuse Optical Spectroscopy functional parameters such as hemoglobin, lipid and water concentration and tissue scattering. Diffuse Optical Spectroscopy imaging can show increase blood flow in breast tissue after ovulation with a concomitant increase in mitotic activity, changes in hemoglobin concentration and in tissue scattering. Increases in fibroglandular breast tissue after ovulation have also been observed. Diffuse Optical Spectroscopy imaging can determine after time of ovulation has been detected during the two months of self-monitoring.