title: Intrapartum fetal weight estimation: a comparison of three formulae.
abstract: To determine the relative accuracy of fetal weight estimation using the biparietal diameter (BPD), the abdominal circumference (AC), and the femur length (FL) in three formulae (BPD/AC, FL/AC, and BPD/AC/FL), 63 patients in labor were examined. All patients delivered within 24 hours of ultrasound examination. A good correlation was found between the estimated fetal weight and the actual birth weight, using the three formulae: BPD/AC (r = 0.96); FL/AC (r = 0.95); and BPD/AC/FL (r = 0.96). The FL/AC formula overestimated fetal weight (P less than 0.01), however, particularly in fetuses weighing more than 2000 g. The mean percentage error with the BPD/AC formula was 0.99 per cent, 3.82 per cent with the FL/AC, and 2.43 per cent with the BPD/AC/FL formula. This study showed that although all three formulae were comparable, the best estimation of the birth weight was obtained when either the BPD/AC or the BPD/AC/FL formulae were used. Additionally, the results demonstrate that reliable estimates of fetal weight can be made even at term or in laboring patients.
mesh_terms: D001724:Birth Weight; D001835:Body Weight; D005260:Female; D005333:Fetus / Q000033:anatomy & histology*; D005865:Gestational Age; D006801:Humans; D007743:Labor, Obstetric; D011247:Pregnancy; D014463:Ultrasonography