Foetal weight estimation, at term, using a multivariate algorithm of maternal characteristics, has an accuracy similar to that of ultrasonography

TL;DR

This study compares a multivariate algorithm using maternal traits to ultrasound for estimating fetal weight at term and finds similar accuracy.

Contribution

A new multivariate algorithm for fetal weight estimation is shown to be as accurate as ultrasound.

Findings

The multivariate algorithm and ultrasound had similar accuracy in estimating fetal weight.

Ultrasound had slightly higher accuracy within 10% of actual birth weight (71.7% vs. 65.2%).

Both methods correlated well with actual birth weight.

Abstract

To compare the accuracy of foetal weight estimation using a multivariate algorithm based on maternal characteristics and pregnancy-specific factors to that of ultrasound.

A cross-sectional hospital-based study.

Antenatal Clinics and Antenatal Labour wards of the Department of Obstetrics & Gynaecology, Federal Medical Centre, Asaba, Nigeria.

A total of 92 pregnant women were admitted for labour, elective caesarean section or elective induction of labour at 37 weeks to 41 weeks and 3 days.

Mean of absolute error, mean of absolute percentage error and proportion of estimated weight within 10% of actual birth weight.

Between April and August 2021, 92 participants were included. An equation based on maternal characteristics was derived. Ultrasound weight estimation was done using Hadlock's 4 formula. Both methods positively correlated with actual birth weight, and their accuracy did not differ significantly. Overall accuracy within 10% of actual birth weight was higher for ultrasonography than multivariate algorithm 71.7% and 65.2%, respectively (χ2=0.286, p=0.60). The mean absolute percentage error was smaller for ultrasound (7.98±4.74%) than clinical formula (9.11±6.76%) p=0.11. The mean absolute error was 265.57±145.67g for ultrasonography and 304.32±203.29g for the multivariate model, with no statistical difference (p=0.09).

The multivariate algorithm based on maternal characteristics and pregnancy-specific factors was equally accurate as ultrasonography for foetal weight estimation at term.

None declared

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