Ultraschall Med 2016; 37 - SL9_4
DOI: 10.1055/s-0036-1587754

Update reference charts: Fetal biometry between the 15th and 20th week of gestation

K Kubiak 1, R Koch 2, W Klockenbusch 3, J Steinhard 4, R Schmitz 3
  • 1St. Franziskus Hospital, Department of Obstetrics and Gynecology, Münster, Germany
  • 2University of Münster, Institute of Biostatistics and Clinical Research, Münster, Germany
  • 3University Hospital of Münster, Department of Obstetrics and Gynecology, Münster, Germany
  • 4Heart and Diabetes Center North Rhine-Westphalia, Department of Fetal Cardiology, Bad Oeynhausen, Germany

Purpose: Reference charts for biometric parameters are a substantial implement of prenatal ultrasound screening. Inaccurate reference charts lead to fault clinical decisions. In our daily practice we observed an over- and underestimation of biometric parameters. The aim of this study was to derive reference charts between the 15th and 20th weeks of gestation for biparietal diameter (BPD), occipito-frontal diameter (OFD), head circumference (HC), abdominal circumference (AC), femur length (FL), compare to commonly used curves and evaluating the impact of maternal BMI, ultrasound equipment, fetal gender, and nicotine abuse.

Material & Methods: In a cross-sectional study of 4,265 low-risk pregnancies, biometric data were obtained between the 15th and 20th weeks of gestation. The statistical analysis included descriptive data, fitting regression curves for the 5th, 50th, 95th quantile and multivariate quantile regression analyses.

Results: Reference curves for BPD, OFD, HC, AU, and FL showed a linear increase between the 15th and 20th week of gestation. New equations and reference charts are presented in this study. In a comparison of influence factors sexes, BMI and ultrasound systems have an impact.

Conclusion: As a result of the study, we determined current growth curves for BPD, OFD, HC, AC, and FL for both sexes as well as for males and females separately. The updated growth curves for all biometrical parameters differ from the curves used commonly in the last two decades.

Fig. 1: Comparison of two reference charts for femurlength