3D and 2D ultrasound-based fetal weight estimation: a single center experience

Evaluate two new 3D and two new 2D ultrasound formulae for fetal weight estimation against the modified Hadlock formula and compare their estimation to the actual fetal weight.

Fifty pregnant females were included.

singleton pregnancy, within five days of delivery and normal or IUGR pregnancy. 3D evaluation of the fetal thigh and arm was done to calculate mid-thigh and mid-arm volumes. The actual fetal weight was recorded at delivery and compared to the estimated weights.

Modified Hadlock formula had higher accuracy, whereas fractional limb volume method had higher precision. Systematic errors for the modified Hadlock formula, Model 6 of fractional limb volume and the original mid-thigh soft tissue thickness methods were 2.3%, -4.8% and 11%, respectively, whereas the random errors were 7.7%, 6.2% and 13.8%, respectively. The percentage of cases estimated within 5%, 10% and 15% of actual fetal weight were 48%, 86% and 92%, respectively, for the modified Hadlock method, whereas for the fractional limb volume method, these were 40%, 78% and 98%, respectively.

Fractional limb volume method is a very promising method for fetal weight estimation. Its performance is not significantly different from the modified Hadlock method.