Effect of Maternal Body Mass Index and Amniotic Fluid Index on the Accuracy of Sonographic Estimation of Fetal Weight in Late Gestation

Matthew J. Blitz; Burton Rochelson; Leah B. Stork; Stephanie Augustine; Meir Greenberg; Cristina P. Sison; Nidhi Vohra

doi:10.1055/s-0037-1618588

American Journal of Perinatology, Table of Contents

Am J Perinatol 2018; 35(13): 1235-1240
DOI: 10.1055/s-0037-1618588

SMFM Fellowship Series Article

Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Effect of Maternal Body Mass Index and Amniotic Fluid Index on the Accuracy of Sonographic Estimation of Fetal Weight in Late Gestation

Authors

Matthew J. Blitz

¹Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Hofstra Northwell School of Medicine, North Shore University Hospital, Manhasset, New York
Burton Rochelson

¹Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Hofstra Northwell School of Medicine, North Shore University Hospital, Manhasset, New York
Leah B. Stork

²Department of Obstetrics and Gynecology, Hofstra Northwell School of Medicine, North Shore University Hospital, Manhasset, New York
Stephanie Augustine

¹Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Hofstra Northwell School of Medicine, North Shore University Hospital, Manhasset, New York
Meir Greenberg

³Division of Medical Informatics, Department of Obstetrics and Gynecology, Hofstra Northwell School of Medicine, North Shore University Hospital, Manhasset, New York
Cristina P. Sison

⁴Biostatistics Unit, Feinstein Institute for Medical Research, Hofstra Northwell School of Medicine, North Shore University Hospital, Manhasset, New York

⁵Department of Molecular Medicine, Hofstra Northwell School of Medicine, Hempstead, New York
Nidhi Vohra

¹Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Hofstra Northwell School of Medicine, North Shore University Hospital, Manhasset, New York

Abstract

Objective The objective of this study was to determine the effect, if any, of maternal body mass index (BMI) and amniotic fluid index (AFI) on the accuracy of sonographic estimated fetal weight (EFW) at 40 to 42 weeks' gestation.

Methods This was a retrospective cohort study of singleton gestations with ultrasound performed at 40 to 42 weeks from 2010 to 2013. In this study, patients with documented BMI and sonographic EFW and AFI, concurrently, within 7 days of delivery were included. Chronic medical conditions and fetal anomalies were excluded from this study. The primary variable of interest was the rate of substantial error in EFW, defined as absolute percentage error (APE) >10%.

Results A total of 1,000 pregnancies were included. Overall, the APE was 6.0 ± 4.5% and the rate of substantial error was 17.4% (n = 174). There was no significant difference in APE or rate of substantial error between BMI groups. In the final multivariable logistic regression model, the rate of substantial error was increased in women with oligohydramnios (OR 1.79; 95% CI: 1.10–2.92). Furthermore, oligohydramnios was significantly more likely to overestimate EFW while polyhydramnios was more likely to underestimate EFW. Maternal BMI did not affect the accuracy of sonographic EFW.

Conclusion Sonographic EFW may be affected by extremes of AFI in the postdates period. Maternal BMI does not affect EFW accuracy at 40 to 42 weeks.

Keywords

estimated fetal weight - amniotic fluid index - oligohydramnios - polyhydramnios - obesity - body mass index

Full Text

References

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