Sonographic Assessment of Fetal Kidney Length for Estimation of Gestational Age in Pregnant Women in Third Trimester Attending a Tertiary Care Centre

Abstract

Introduction: Accurately estimating fetal gestational age holds tremendous significance for the outcome of pregnancy. Besides existing parameters for estimating gestational age, fetal kidney length can be used as an alternative technique for measuring gestational age in the third trimester of pregnancy. This study aimed to measure fetal kidney length in pregnant women in their third trimester of pregnancy visiting a tertiary care centre.

Methods: This was a descriptive cross-sectional study conducted among uncomplicated pregnancies in their third trimester (28-40 weeks) visiting a tertiary care centre after obtaining the ethical approval from the Institutional Review Board. Women who were sure of their last menstrual period were included in the study. Women with medical illness or anomalies in fetal kidney were excluded from the study. The length of both fetal kidneys was measured and an average of the length of the two kidneys was taken to see whether it showed a linear increment with increased gestational age.

Results: Among 100 pregnant women, fetal kidney length showed a linear increment with increased gestational age. Among 100 women, 43 (43%) were in the age group 20-24 years. The lowest mean kidney length measured at 28 weeks of gestation was 29 mm while the maximum mean kidney length measured at 40 weeks of gestation was 38.5 mm.

Conclusions: Fetal kidney length has a steady growth rate throughout pregnancy, and it can easily be included in routine obstetric scans to improve gestational age measurement accuracy in the third trimester.