Assessment of renal maturity by assisted morphometry in autopsied fetuses.

BACKGROUND: The kidney is one organ which presents distinct morphology depending on GA; the classic references for kidney measurements were established several years ago and it is not certain if they are still accurate. AIM: To evaluate the renal maturity using a computer-assisted morphometry in autopsied fetuses within 20 to 40 weeks of GA. STUDY DESIGN: Microscopic hematoxylin and eosin stained renal sections from 67 stillborns were utilized for the morphometric analyses. RESULTS: It was possible to promote an adjustment in the formula used to calculate the number of mature glomeruli layers to the GA (GLN = 0.212GA + 0.0169) in autopsy material and it was different from the literature (Sr = 0.709; p < 0.001). Regarding the nephrogenic zone, it decreases with the GA as confirmed by the regression equation NZ = 490.7-(11.9 x GA) (p < 0.001; Sr = -0.685). CONCLUSION: In conclusion, our data contribute to the evaluation of renal maturity and GA in autopsied fetuses, showing particular importance in autolyzed fetuses, in which the parameters used in the present study can still be applied. The correction of the formula for counting mature glomeruli layers for each GA and the addition of new morphometric parameters for the evaluation of renal maturity increase the precision for the analysis of spontaneous abortion and autopsy material, improving the correlation with pathological processes in clinical findings and in the other organs.