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Sonographic fetal weight estimation – is there more to it than just fetal measurements?
Author(s) -
Barel Oshri,
Maymon Ron,
Vaknin Zvi,
Tovbin Josef,
Smorgick Noam
Publication year - 2014
Publication title -
prenatal diagnosis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.956
H-Index - 97
eISSN - 1097-0223
pISSN - 0197-3851
DOI - 10.1002/pd.4250
Subject(s) - medicine , fetal weight , obstetrics , gestational age , amniotic fluid index , birth weight , fetus , body mass index , pregnancy , sonographer , mass index , amniotic fluid , ultrasonography , surgery , genetics , biology
Objectives The primary aim of this study was to evaluate the effects of different maternal, fetal, and examiner related factors on the accuracy of sonographic fetal weight estimation (SFWE). Methods A retrospective cohort study analyzing 9064 SFWEs performed within 1 week prior to delivery, including singleton pregnancies with a gestational age of 37 to 42 weeks, was recorded at one medical center from January 2004 to September 2011. Predicted birth weights were calculated according to models by Sabbagha et al ., Hadlock et al ., and Combs et al . and were compared with the actual birth weight. Effects of different factors on SFWE accuracy were assessed. The systematic error, random error, and mean absolute percentage error were used as measures of accuracy. Results High maternal weight, height, body mass index, multiparity, older maternal age, diabetes, and fetal male sex were associated with underestimation of SFWE ( P < 0.05). Fetal presentation and the sonographer's experience influenced SFWE differently using various models. The amniotic fluid index did have a significant effect on SFWE. Overall, more than 90% of the systematic errors were unaccounted for in the factors we assessed. Conclusions Many maternal and fetal factors significantly influence the SFWE; nevertheless, most errors are probably due to inherent problems in SFWE formulas. © 2013 John Wiley & Sons, Ltd.