Accuracy of Fetal Kidney Length and Transcerebellar Diameter In Determination of Fetal Gestational Age in Mid Trimester in Healthy Women

Abstract

Accurate assessment of gestational age (GA) is pivotal to provide good quality maternity care. Reliability of routinely used ultrasonographic biometric parameters like Biparietal diameter (BPD), Head circumference (HC) and Femur length (FL) decrease with increasing GA.Fetal kidney length (FKL) and transverse cerebellar diameter (TCD) have been shown to strongly correlate with GA in 2nd and 3rd trimester.The present study was conducted on 150 pregnant women at 20 weeks of gestation to evaluate the role of FKL and TCD in estimation of GA and compare their accuracy with other established biometric indices. The GA of the included women was confirmed by early dating scan and exact Last Menstrual Period (LMP).BPD,HC,FL,FKL and TCD were calculated in millimetres (mm) and GA was calculated by using these parameters individually. Standard deviation and standard error of the GA calculated at 20 weeks was lesser for TCD and FKL than BPD, HC and FL with p values of 0.01636 and 0.0129 respectively. It was also observed that values of TCD and FKL in mm correspond to GA in weeks. So it was concluded that FKL and TCD can be used as an individual parameter in estimating GA in mid trimester in patients presenting for the first time with uncertain dates, lack of early dating scan or with IUGR.