Korean Journal of Nephrology 1995;14(4):454-459.

(Measurement of Fetal Kidney Size and Groqth Ultrasonography)

Kyosun Kim , Jeong Hee Park

Abstract

Sonographic standards of normal fetal kidney size were determined in 229 fetuses after 20 weeks gestation. Fetal kidneys were identified from 20th gestational week. Fetal kid- ney lengths increase as pregnancy progresses (2.10±0.20 cm, 2.34±0.27 cm, 2.82±0.30 cm, 3.34±0.26 cm, 3.60±0.23 cm and 3.75±0.37 cm at 20, 24, 28, 32, 36 and 40 gestational week). Mean fetal kidney widths were reported for each gestational age (1.25 cm, 1.24 cm, 1.58 cm, 1.81 cm, 1.89 cm and 1.98 cm at 20, 24, 28, 32, 36 and 40 gestational week). Regression equations to estimate the fetal kidney size (length and width) were obtained as follows, kidney length (cm)=0.50±0.087 x gestational age (week) (r=0.8130, p<0.001) =0.31+ 0.361 x biparietal diameter (BPD) (cm) (r=0.8091, p<0.001) =1.20+ 0.339 x femur length (cm) (r=0.7691, p<0.001), kidney width (cm)=0.21+0.047 x gestational age (week) (r=0.6968, p<0.001)=0.13+0.199 X BPD (cm) (r=0.6786, p<0.001)=0.62+0.186 x femur length (cm) (r=0.6449, p<0.001). In conclusion, kidney size showed a linear corre- lation to gestational age. Kidney size could be calculated from the above equations. We established that the growth rate of fetal kidney length and width was 0.87 mm and 0.47 mm per week after 20th gestational week, respectively.