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Accuracy of Estimated Fetal Weight below 1,000g
Author(s) -
Scott Fergus,
Beeby Philip,
Abbott Jason
Publication year - 1996
Publication title -
australian and new zealand journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.734
H-Index - 65
eISSN - 1479-828X
pISSN - 0004-8666
DOI - 10.1111/j.1479-828x.1996.tb03267.x
Subject(s) - fetal weight , fetus , medicine , obstetrics , birth weight , pregnancy , caesarean section , biology , genetics
EDITORIAL COMMENT: We accepted this paper for publication because it gives useful information on the interpretation of ultrasonographic estimates of fetal weight when considering whether fetal viability is such that Caesarean section is indicated on fetal grounds as the method of delivery in a complicated pregnancy. Summary: The Wars of formula is 1 of 3 currently recommended by the Australian Society for Ultrasound in Medicine for the routine estimation of fetal weight. However, this formula was derived using mostly large fetuses, and its accuracy in extremely low birth‐weight fetuses is not known. Using this formula, we studied 184 infants delivering within 14 days of an estimated fetal weight (EFW) <1,000 G, The mean percent error in EFW was 11.7% underestimation, with 80% of infants underestimated and 61% of estimates within 15% error. The percent error was consistent at 9.6% throughout the first 9 days, but increased to 32% after 10 days post scan (p<0.0001). There was a significant association between the accuracy of EFW and maternal height, but not with placental position, liquor volume or multiple pregnancy. EFW underestimated birth‐weight on average by 9.6% during the first week, and this error appeared to be mainly due to the formula. The error in EFW became unacceptable after 9 days and repeating the estimate before 10 days is recommended. A different formula may be more suitable for extremely low birth‐weight fetuses.