Finding the most accurate method to measure head circumference for fetal weight estimation

Ulrike Schmidt; Dunja Temerinac; Katharina Bildstein; Benjamin Tuschy; Jade Mayer; Marc Sütterlin; Jörn Siemer; Sven Kehl

doi:10.1016/j.ejogrb.2014.03.047

Finding the most accurate method to measure head circumference for fetal weight estimation

Eur J Obstet Gynecol Reprod Biol. 2014 Jul:178:153-6. doi: 10.1016/j.ejogrb.2014.03.047. Epub 2014 Apr 14.

Authors

Ulrike Schmidt¹, Dunja Temerinac², Katharina Bildstein³, Benjamin Tuschy¹, Jade Mayer¹, Marc Sütterlin², Jörn Siemer⁴, Sven Kehl⁵

Affiliations

¹ Department of Obstetrics and Gynecology, University Medical Centre Mannheim, Heidelberg University, Mannheim, Germany.
² Department of Obstetrics and Gynecology, University Medical Centre Mannheim, Heidelberg University, Mannheim, Germany; Department of Obstetrics and Gynecology, Stadtklinik Frankenthal, Frankenthal, Germany.
³ Department of Obstetrics and Gynecology, Stadtklinik Frankenthal, Frankenthal, Germany.
⁴ Department of Obstetrics and Gynecology, Klinikum Pforzheim, Pforzheim, Germany.
⁵ Department of Obstetrics and Gynecology, University Medical Centre Mannheim, Heidelberg University, Mannheim, Germany; Department of Obstetrics and Gynecology, Erlangen University Hospital, Erlangen, Germany. Electronic address: sven.kehl@gmail.com.

PMID: 24802187
DOI: 10.1016/j.ejogrb.2014.03.047

Abstract

Objective: Accurate measurement of fetal head biometry is important for fetal weight estimation (FWE) and is therefore an important prognostic parameter for neonatal morbidity and mortality and a valuable tool for determining the further obstetric management. Measurement of the head circumference (HC) in particular is employed in many commonly used weight equations. The aim of the present study was to find the most accurate method to measure head circumference for fetal weight estimation.

Study design: This prospective study included 481 term pregnancies. Inclusion criteria were a singleton pregnancy and ultrasound examination with complete fetal biometric parameters within 3 days of delivery, and an absence of structural or chromosomal malformations. Different methods were used for ultrasound measurement of the HC (ellipse-traced, ellipse-calculated, and circle-calculated). As a reference method, HC was also determined using a measuring tape immediately after birth. FWE was carried out with Hadlock formulas, including either HC or biparietal diameter (BPD), and differences were compared using percentage error (PE), absolute percentage error (APE), limits of agreement (LOA), and cumulative distribution.

Results: The ellipse-traced method showed the best results for FWE among all of the ultrasound methods assessed. It had the lowest median APE and the narrowest LOA. With regard to the cumulative distribution, it included the largest number of cases at a discrepancy level of ±10%. The accuracy of BPD was similar to that of the ellipse-traced method when it was used instead of HC for weight estimation.

Conclusion: Differences between the three techniques for calculating HC were small but significant. For clinical use, the ellipse-traced method should be recommended. However, when BPD is used instead of HC for FWE, the accuracy is similar to that of the ellipse-traced method. The BPD might therefore be a good alternative to head measurements in estimating fetal weight.

Keywords: Biparietal diameter; Fetal weight estimation; Head circumference; Measurement; Ultrasound.

MeSH terms

Adult
Cephalometry*
Female
Fetal Weight*
Head / diagnostic imaging*
Humans
Pregnancy
Pregnancy Trimester, Third
Prospective Studies
Ultrasonography, Prenatal / methods*