Accurate ultrasonic estimation of fetal weight. Prospective analysis of new ultrasonic formulas.

: Five new ultrasonic weight formulae incorporating head circumference, fetal femur length, and a correction for oligohydramnios were prospectively analyzed in a group of 198 unselected patients scanned within 72 hours of birth. Comparison with the Shepard formula showed that inclusion of these parameters slightly, but significantly, improved the random error of weight estimation. The best-fit formula was: Log(10) BW = .04355HC + .05394AC - .0008582HC X AC + 1.2594 (FL/AC) - 2.0661.