Fetal weight estimation at term – ultrasound versus clinical examination with Leopold’s manoeuvres: a prospective blinded observational study

Abstract

Background Fetal weight estimation is of key importance in the decision-making process for obstetric planning and management. The literature is inconsistent on the accuracy of measurements with either ultrasound or clinical examination, known as Leopold’s manoeuvres, shortly before term. Maternal BMI is a confounding factor because it is associated with both the fetal weight and the accuracy of fetal weight estimation. The aim of our study was to compare the accuracy of fetal weight estimation performed with ultrasound and with clinical examination with respect to BMI. Methods In this prospective blinded observational study we investigated the accuracy of clinical examination as compared to ultrasound measurement in fetal weight estimation, taking the actual birth weight as the gold standard. In a cohort of all consecutive patients who presented in our department from January 2016 to May 2017 to register for delivery at ≥37 weeks, examination was done by ultrasound and Leopold’s manoeuvres to estimate fetal weight. All examiners (midwives and physicians) had about the same level of professional experience. The primary aim was to compare overall absolute error, overall absolute percent error, absolute percent error > 10% and absolute percent error > 20% for weight estimation by ultrasound and by means of Leopold’s manoeuvres versus the actual birth weight as the given gold standard, namely separately for normal weight and for overweight pregnant women. Results Five hundred forty-three patients were included in the data analysis. The accuracy of fetal weight estimation was significantly better with ultrasound than with Leopold’s manoeuvres in all absolute error calculations made in overweight pregnant women. For all error calculations performed in normal weight pregnant women, no statistically significant difference was seen in the accuracy of fetal weight estimation between ultrasound and Leopold’s manoeuvres. Conclusions Data from our prospective blinded observational study show a significantly better accuracy of ultrasound for fetal weight estimation in overweight pregnant women only as compared to Leopold’s manoeuvres with a significant difference in absolute error. We did not observe significantly better accuracy of ultrasound as compared to Leopold’s manoeuvres in normal weight women. Further research is needed to analyse the situation in normal weight women.

Accuracy of ultrasound in estimating fetal weight in New Zealand

“…Other studies prior to 2006 reported fetal weight estimation accuracies that varied between 23 and 78%, 6 but few of these distinguished between overestimated and underestimated group features. More recent studies from other countries have similar degrees of accuracy to ours but they have different population demographics such as lower mean maternal ages, weights and normal range BMI, 5,9 compared with our average BMI of 27kg/m 2 which is classified as overweight.…”

Comparison between clinical estimated fetal weights (CEFW) Versus Ultrasonographic estimated fetal weight (UEFW) for co-relation with actual birth weight (ABW) in 3rd Trimester of Pregnancy

“…Accurate prenatal estimation of birth weight is useful in the management of labour and delivery, permitting obstetricians to make decisions about instrumental vaginal delivery, trial of labour for patients suspected of having a low birth weight or macrosomic fetus (1). According to the existing literature, there is no truly accurate technique for evaluating FW (2). Before delivery, accurate estimation of FW can have a major approach for decision and management of labour, perinatal outcome can be improved better (3).…”

“…Estimation of FW can be done by external abdominal measurements, alone or associated with fundal height measurement and/or USG scan near 32 weeks (4). Since the advent of ultrasound and its dissemination over the last three decades, and despite the lack of conclusive evidence, there has been a widespread belief that ultrasound is more accurate than other methods for predicting fetal weight (2).…”

Accuracy of Ultrasound Estimation of Fetal Weight at Three Teaching Hospitals in Addis Ababa

“…EFW in late pregnancy or before delivery is often an important variable in clinical decision-making in obstetrics. Fetal weight estimation is of key importance in the decision-making process for obstetric planning and management (1).…”