ABSTRACT
PURPOSE: Alterations in renal dimensions may be an early manifestation of deviation from normality, with possible repercussions beyond intrauterine life. The objective of this study was to establish reference curves for fetal kidney dimensions and volume from 14 to 40 weeks of gestation. METHODS: This is a prospective longitudinal study of 115 Brazilian participants in the "WHO multicentre study for the development of growth standards from fetal life to childhood: the fetal component". Pregnant women with clinical and sociodemographic characteristics allowing the full potential fetal growth were followed up from the first trimester until delivery. These women underwent serial sonographic evaluation of fetal kidneys. The longitudinal, anteroposterior and transverse diameters of both fetal kidneys were measured, in addition to calculation of kidney volume. By quantile regression analysis, reference curves of renal measurements related to gestational age were built. RESULTS: Standard normal sonographic values of renal biometry were defined during pregnancy. Reference values for the 10th, 50th and 90th centiles of different fetal kidney measurements (longitudinal, anteroposterior, transverse and volume) from the 14th to the 40th week of gestation were fitted. CONCLUSION: The reference curves presented should be of the utmost importance for screening and diagnosis of alterations in renal development during the intrauterine period.