Scientific basis for standardization of fetal head measurements by ultrasound: a reproducibility study

Objective To compare the standard methods for ultrasound measurement of fetal head circumference (HC) and biparietal diameter (BPD) (outer‐to‐outer (BPDoo) vs outer‐to‐inner (BPDoi) caliper placement), and compare acquisition of these measurements in transthalamic (TT) vs transventricular (TV) planes. Methods This study utilized ultrasound images acquired from women participating in the Oxford arm of the INTERGROWTH‐21st Project. In the first phase of the study, BPDoo and BPDoi were measured on stored images. In the second phase, real‐time measurements of BPD, occipitofrontal diameter (OFD) and HC in TT and TV planes were obtained by pairs of sonographers. Reproducibility of measurements made by the same (intraobserver) and by different (interobserver) sonographers, as well as the reproducibility of caliper placement and measurements obtained in different planes, was assessed using Bland–Altman plots. Results In Phase I, we analyzed ultrasound images of 108 singleton fetuses. The mean intraobserver and interobserver differences were
Linked Comment: Ultrasound Obstet Gynecol 2016; 48: 26–26