The study was planned to obtain the dimensions of the fetal nose width and nostril distance during normal pregnancy as a basis for further studies and for identification of deviations in growth. The study group included 302 healthy pregnant women at 14-40 weeks' gestation. Routine biometric measurements were obtained from all the participants, including biparietal diameter, head and abdominal circumferences, measurements of the long bones and dimensions of the fetal nose width and nostril distance. The nose width and nostril distance were also calculated for each gestational age. A linear growth relationship was observed between nose width and gestational age (r = 0.88; p < 0.0002; y = 0.27 + 0.57 x gestational age), biparietal diameter (r = 0.92; p < 0.0001; y = 0.41 + 0.23 x biparietal diameter), head circumference (r = 0.91; p < 0.00001; y = 0.85 + 0.63 x head circumference), femoral length (r = 0.91; p < 0.0001; y = 3.18 + 0.26 x femoral length) and humeral length (r = 0.73; p < 0.0001; y = 1.94 + 0.11 humeral length). A linear growth function was also observed between nostril distance and gestational age (r = 0.54; p < 0.00001; y = 2.77 + 0.15 x gestational age), biparietal diameter (r = 0.71; p < 0.00001; y = 1.83 + 0.08 x biparietal diameter), head circumference (r = 0.70; p < 0.00001; y = 1.99 + 0.2 x head circumference), femoral length (r = 0.75; p < 0.00001; y = 2.49 + 0.09 x femoral length) and humeral length (r = 0.91; p < 0.00001; y = 1.89 + 0.32 x humeral length). A linear growth relationship was found between nose width and nostril distance (r = 0.71; p < 0.00001; y = 1.81 + 0.31 x nose width). These results provide normative data of the fetal nose width and nostril distance in various dimensions and across gestational age. In addition, the data offer the potential for prenatal diagnosis of nose and nostril abnormalities.
