Reliability of sonographic fetal weight estimation in triplet pregnancies: a retrospective cohort study

Purpose

To review our experience in ultrasound fetal weight estimation in our large population of triplet pregnancies.

Methods

Ninety-seven triplet pregnancies were retrospectively included between January 2003 and January 2017. Sonographic fetal weight estimation using Hadlock’s and Schild’s formulas was compared to actual birth weight in a tertiary-care center in Vienna, Austria. Statistical analyses were performed using a stepwise linear regression model and crosstabs.

Results

The median discrepancy between the sonographically estimated fetal weight by Hadlock’s formula and the actual birth weight was 106 g (IQR 56–190). The percentage error and its standard deviation were ??2.5?±?12.1%, and the median percentage error was ??3.6%. Concerning the use of Hadlock’s formula, estimated fetal weight was the most important factor predictive of actual birth weight with an estimate of 0.920 (p?p?

Conclusion

Even if sonographically estimated fetal weight in triplet pregnancies has a high overall accuracy of fetal weight estimation, there are some limitations in prediction of intrauterine growth restrictions, especially in female fetuses.