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Sonographic estimation of fetal weight in maerosomic fetuses: diabetic versus non‐diabetic pregnancies
Author(s) -
Wong SF,
Chan FY,
Cincotta RB,
Oats JJ,
Mclntyre HD
Publication year - 2001
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.2001.tb01323.x
Subject(s) - medicine , diabetes mellitus , fetus , fetal weight , birth weight , obstetrics , pregnancy , endocrinology , biology , genetics
SUMMARY The objective of this study is to compare the accuracy of sonographic estimation of fetal weight of maerosomic babies in diabetic vs non‐diabetic pregnancies. All babies weighing 4000 g or more at birth, and who had ultrasound scans performed within one week of delivery were included in this retrospective study. Pregnancies with diabetes mellitus were compared to those without diabetes mellitus. The mean simple error (actual birthweight ‐ estimated fetal weight); mean standardised absolute error (absolute value of simple error (g)/actual birthweight (kg)); and the percentage of estimated birthweight falling within 15% of the actual birthweight between the two groups were compared. There were 9516 deliveries during the study period. Of this total 1211 (12.7%) babies weighed 4000 g or more. A total of 56 non‐diabetic pregnancies and 19 diabetic pregnancies were compared. The average sonographic estimation of fetal weight in diabetic pregnancies was 8% less than the actual birthweight, compared to 0.2% in the non‐diabetic group (p < 0.01). The estimated fetal weight was within 15% of the birthweight in 74% of the diabetic pregnancies, compared to 93% of the non‐diabetic pregnancies (p < 0.05). In the diabetic group, 26.3% of the birthweights were underestimated by more than 15 %, compared to 5.4% in the non‐diabetic group (p < 0.05). In conclusion, the prediction accuracy of fetal weight estimation using standard formulae in maerosomic fetuses is significantly worse in diabetic pregnancies compared to non‐diabetic pregnancies. When sonographic fetal weight estimation is used to influence the mode of delivery for diabetic women, a more conservative cut‐off needs to be considered.