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

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.

Fetal Femur Length in Assessment of Gestational Age in Third Trimester in Women of Northern India (Lucknow, UP) and a Comparative Study with Western and Other Asian Countries.

Introduction: Gestational age (GA) estimation is the most important part of obstetric practice and ultrasonic study plays an important role in its accurate estimation. Fetal femur length (FL) is one of the parameters used for estimation of GA along with biparietal diameter, head circumference and abdominal circumference (AC). Objective: This study is an attempt to correlate fetal FL with GA and to ascertain if fetal FL can be used as a parameter to calculate the GA in third trimester of pregnancy in Indian women with moderate accuracy. Findings have been compared with the work of sonologists from other countries. Material and methods: Pregnant women in the third trimester of pregnancy with single live fetus and having no other complication either in mother or fetus, were selected for the study, fetal FL along with other parameters was measured. The results were analyzed for accuracy in estimation of GA by FL and were compared with findings of other workers. Result: GA estimated from FL in 512 cases between 27-39 weeks of gestation showed that quadratic model has a good fit to the data and r2 = 0.785 with standard error + 8 days. There was a significant difference with Iranians and Bangladesh women in comparison to our findings. The paired t-test between Indian and Bangladesh, women was significant, (p < 0.001). The findings in our study were similar to the results of Western fetal FLs. Conclusion: The data can be useful in estimation of GA by FL. Our error was + 8 days. A bigger study involving same number of cases in each week of gestation in third trimester is necessary to get an accurate formula for assessment of GA by FL.