ABSTRACT
OBJECTIVE: To establish size ranges of normal fetal kidneys by ultrasonogram during pregnancy. METHODS: The A-P diameter and length of each of 450 kidneys in 225 consecutive fetuses between 19 and 41 weeks of gestation were measured on sonogram from March to August 2001 in Samsung Medical Center. Gestational ages were determined by last menstrual period and Crown-Rump Lengths of early stage of pregnancy. Abnormal fetuses, twins, offspring of diabetic mothers, and fetuses with renal pelvic dilatation of 5 mm or greater were excluded to avoid any questionable measurements. RESULTS: The results showed normal distribution and results were similar to previous reports. There was a strong correlation between fetal renal size and gestational age, but no significant difference between right and left renal sizes in fetuses. Average A-P diameter and renal lengths were significantly different when compared across the range of gestational ages (p<.001). CONCLUSION: As long as we know, this was the first report of size of the normal fetal kidney sonographically during pregnancy in Korea. We think that these results can be used to detect abnormality of fetal kidney and to estimate uncertain gestational age.