We evaluated the feasibility of demonstration of the embryonic cerebral ventricles using three dimensional transvaginal ultrasonography and software which has been developed to automatically calculate the volume of ovarian follicles after ovarian stimulation. In four out of six subsequent ultrasound examinations which were done for determination of gestational age from eight to ten gestational weeks, sufficient resolution was obtained to demonstrate the embryonic cerebral ventricles with automated volume calculation software, yielding striking images of a dramatic stage of embryonic development.