Fetal head and abdominal circumferences: II. A critical re-evaluation of the relationship to menstrual age

✍ Scribed by Russell L. Deter; Ronald B. Harrist; Frank P. Hadlock; Robert J. Carpenter

• Publisher: John Wiley and Sons
• Year: 1982
• Tongue: English
• Weight: 638 KB
• Volume: 10
• Category: Article
• ISSN: 0091-2751
• DOI: 10.1002/jcu.1870100804

✦ Synopsis

Abstract

Dynamic image ultrasound was utilized to re‐examine the changes in head and abdominal circumferences (HC, AC) with gestational age in normal fetuses. Data collected in a cross‐sectional study of fetal growth were evaluated using mathematical modeling techniques. The results of this analysis indicated that a linear‐cubic function optimally fits the HC data (R^2^ = 97.3%) while the AC data was fitted optimally by a linear function (R^2^ = 95.5%). The predicted values calculated from these functions were in very close agreement [mean deviation (absolute value): 1.97% (HC), 1.38% (AC)] with those calculated from average functions for HC and AC obtained in a previous longitudinal growth study. Variability was not constant throughout pregnancy for either HC or AC. With HC the normal range changed from ±1.5 cm to ±2.5 cm at 28 wk (menstrual age). The AC variability increased progressively with increasing menstrual age and was shown to be related to the predicted AC value. The normal range was found to be 13% of the predicted AC value throughout pregnancy. Based on these results, a new set of normal HC and AC values for the 12–40 wk (menstrual age) period is presented.