Accuracy of sonographic fetal weight estimation within 14 days of delivery in a Jordanian population using Hadlock formula 1.

OBJECTIVES To assess the accuracy of sonographic fetal weight estimation within 14 days of delivery in a Jordanian population using Hadlock formula 1 in the third trimester. MATERIALS AND METHODS Estimated fetal weights and actual fetal weights data were collected from the medical records of pregnant women who had undergone sonographic fetal weight estimation within 14 days of delivery over the period of March 2008 to June 2010. The analysis included 409 Jordanian women; 6 of them had twins, so the study involved estimation of 415 fetal weights, and these were compared to the actual recorded neonatal weights. Using Hadlock formula 1, we compared the estimations with the infants' actual birth weights. The data were analyzed in 2 groups: within 7 days and 8-14 days. RESULTS The mean estimated fetal weight was 3,133 ± 475 g (range 1,343-4,420 g). The mean actual birth weight was 3,179 ± 450 g (range 1,300-4,450 g). The mean absolute percentage of error of ultrasound fetal weight estimation for all infants was 6.5%; however, it was 6.1 and 8.2% if the fetus was delivered within 7 days or 8-14 days of sonography, respectively. Overall, 78.8% of fetal weight estimations were within 10% of actual birth weight; however it was 81.3 and 69.9% if the fetus was delivered within 7 days or from 8-14 days of sonography, respectively. CONCLUSION The use of Hadlock formula 1 for sonographic fetal weight estimations in Jordanian women showed acceptable results relative to the actual neonatal weight at birth. However, fetal weight estimation was more reliable when performed within 7 days of delivery.