Accuracy of ultrasonic weight prediction in the fetus with preterm premature rupture of membranes.

The accuracy of ultrasonic fetal weight prediction in the low birth weight fetus was evaluated, comparing measurement errors in 86 fetuses with premature rupture of membranes with 112 fetuses with intact membranes. Using two ultrasonic formulas for estimation of fetal weight, we found no significant differences in the mean error of ultrasonic weight measurement between these groups. In both groups, the mean measurement error was approximately 9%, with a standard deviation of 7%. It appears that ultrasonic methods for estimation of fetal birth weight are equally applicable to preterm fetuses with or without ruptured membranes.