Ultrasonographic estimate of birth weight at 24 to 34 weeks: A multicenter study

S. P. Chauhan, S. F. Charania, R. A. McLaren, L. D. Devoe, E. L. Ross, N. W. Hendrix, J. C. Morrison

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


OBJECTIVE: The study was intended to compare the accuracies of ultrasonographic estimates of birth weights among infants born between 24 and 34 weeks' gestation at 3 tertiary centers. STUDY DESIGN: In this retrospective study subjects were matched for gestational age (1:1); all underwent ultrasonographic examination within 2 weeks of delivery. The estimates of birth weight were obtained according to 26 published regression equations and their accuracies were assessed with the mean standardized absolute error. For each center the equation with the lowest error was selected to generate (1) receiver-operating characteristic curves for an estimate to identify actual weight <1500 g and (2) prediction limit calculations to determine the estimate that ensures at 70% confidence a birth weight >1500 g. RESULTS: One hundred seventy-one cases were analyzed at each center. Comparison of the 26 mean standardized errors at each center indicated that (1) the range was rather wide (eg, 89 ± 87 to 365 ± 313 g/kg) and (2) 73% (19/26) of the equations had significantly (P < .05) different accuracies. Receiver-operator characteristic curves show that fetal weight estimates of >1600 g at 2 centers and >1700 g at the third center are required to predict actual birth weight <1500 g. Prediction limit calculation suggests that different fetal weight estimates (>1600 g at center I, >1900 g for the center II, and >1800 g at center III) are needed to predict actual weight > 1500 g with a 70% accuracy. CONCLUSIONS: Ultrasonographic estimates of weight for preterm infants, as obtained from 26 equations, are characterized by a rather wide range of accuracy; for most of the equations the accuracies of estimates differ markedly among centers.

Original languageEnglish (US)
Pages (from-to)909-916
Number of pages8
JournalAmerican journal of obstetrics and gynecology
Issue number4
StatePublished - 1998
Externally publishedYes


  • Estimated fetal weight
  • Preterm delivery

ASJC Scopus subject areas

  • Obstetrics and Gynecology


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