Transvaginal Sonographic Fetal Biparietal Diameter/Kidney Length Ratio in Early Pregnancy as a Screening Tool for Renal Malformations

Abstract

Objective: The aim of the study was to produce by 7.0 MHz high resolution transvaginal scan early in pregnancy normal values of biparietal diameter/kidney length ratio that can be used as reference ranges. Methods: In this prospective cross-sectional study, a transvaginal high-resolution sonography was performed between 11 and 16 weeks’ gestation in 807 pregnant women with a history of regular cycles, singleton pregnancies and absence of fetal malformations. Measurements of kidney length and biparietal diameter were obtained in all cases and biparietal diameter/kidney length ratio was plotted against gestational age. Results: The values of biparietal diameter/kidney length ratio were found to be fairly constant throughout the period evaluated. Conclusion: Our results indicate that this new age-independent ratio can be useful in the early detection of some fetal kidney malformations affecting normal growth.

What is biparietal diameter/kidney length ratio in cases with renal hyperechogenicity?

“…Our nomogram was not significantly different from the previous data [3,4]. The values appear to be fairly constant throughout pregnancy, with a slight decrease.…”

“…We compared our nomogram for biparietal diameter/kidney length ratio plotted against gestational age with data from Callan et al [3] and Guariglia Rosati [4]. Our nomogram was not significantly different from the previous data [3,4].…”

“…Some authors have proposed ratios, in different stages of pregnancy, as a screening tool for the detection of abnormal kidney growth [3,4]. Normal standards established for kidney length in term infants, premature infants, and children as measured with ultrasonography have facilitated accurate evaluation of abnormal kidneys [3,4,5,6,7,8].…”