The effect of breast stimulation on cervical ripening was studied. One hundred patients who had completed 38 weeks' gestation and had uncomplicated antenatal courses were recruited and divided into two groups: treatment and control. In the treatment group, gentle breast stimulation of alternate breasts was performed first for 1.5 hours under monitoring in the hospital and then for three hours daily for three days at home. No uterine hypertonus was detected. It was found that there was a significant change in the Bishop score of 3.96 +/- 1.34 points in the stimulated group as compared with the control group 1.04 +/- 1.03 points. After three days, a cross-over trial was performed with the extreatment group becoming the control and the excontrol group undergoing breast stimulation for the same period of time and under the same conditions. Again, the excontrol group was found to have a better mean cervical score (3.11 +/- 1.42 points) than the extreatment group (0.76 +/- 0.97 points) during breast stimulation. It is stressed that no uterine hypertonus was detected with gentle, unilateral breast stimulation, and there were no maternal or fetal complications as a result of this modality of cervical ripening.