Vaginal ultrasound gauge of 7 MHz frequency (Brüel and Kjaer) was used to examine 70 pregnant women. These women were referred to the prenatal counselling center due to previous deliveries of babies with CNS defects or other anatomical or genetic abnormalities. Ultrasound scans were carried out in the 8th to 12 ve week of gestation. The authors suggest that ultrasound enables precise assessment of fetal CNS in the I trimester already (visible skull and cerebral ventricles after 8-9 weeks, spine--after 9-10 weeks). Authors' findings are documented photographically.