Accuracy in Estimation of Gestational Age in Third Trimester by Fetal Kidney Length in Indian Women.

ABSTRACT

Introduction: Accuracy in estimation of gestational age (GA) has become more demanding as technology used in sonography has become more advanced. Patient’s expectations have also increased and they expect exact estimations to plan their pregnancies. Fetal kidney length (FKL) alone or in combination with other biometric indices can be used in estimating GA more precisely. Objective: The study aimed in measuring FKL and calculating GA using it as a single parameter and comparing the accuracy when combined with other biometric parameters used in estimation of GA on ultrasonography in third trimester in Indian women. Material and methods: Healthy pregnant women in third trimester with single live fetus with no maternal or fetal complications were selected for the study. FKL along with other biometric parameters were measured. The results were analyzed for finding if FKL could be used as a single parameter in estimation of GA and if the accuracy improved if combined with other indices. Results: GA was estimated in 715 cases by all four parameters in the women who came in the third trimester for ultrasonography. FKL was also measured simultaneously in these women. It was observed that average FKL increased linearly from 30.7 mm at 27 weeks to 39.4 mm at 38 weeks. Mean left kidney length was slightly but significantly more than the right kidney. GA was estimated by FKL alone and it gave results with SE ± 10.45 days and when combined with other indices accuracy improved to SE ± 5.45 days. Conclusion: FKL can be a single lone parameter in estimation of GA to give an accuracy of SE ± 10.45 days, but when used in combination with other four indices the accuracy increased to SE ± 5.5 days.