EP04.02: Coronal plane as an alternative plane of measurement of the nasal bone in the mid‐trimester of pregnancy: a cross‐sectional study

To determine the compatibility of measurements of the nasal bone length obtained from the mid-sagittal and coronal planes on fetuses 18 to 28 weeks age of gestation and establish if measurement in the coronal plane is an acceptable alternative to the current standard method of measurement in the mid-sagittal plane. This was a single-centre cross-sectional study covering real-time transabdominal scans among 103 patients on their 18-28 weeks age of gestation. The fetal nasal bone was measured on the mid-sagittal plane using the standard method, as well as on the coronal plane. Measurements were compared using the paired sample T-test and the Pearson correlation analysis was used to determine the correlation between mid-sagittal and coronal measurements. The Mann–Whitney U test was used to compare the nasal bone measurements at different gestational ages and the Kruskal-Wallis test to determine if the difference between the coronal and mid-sagittal measurements in each group is significant. Lengths of the nasal bones ranged from 4.8 to 11.3mm in the mid-sagittal view and 3.5 to 11.4mm in the coronal view. When the results were grouped according to gestational age and a comparison between the two planes of measurement were made, it was found that there was no significant difference between the mid-sagittal and coronal measurements in all groups. There was no significant difference between nasal bone length measurements in the mid-sagittal and coronal planes among patients on their 18 to 28 weeks age of gestation, hence, measurement in the coronal plane is an acceptable alternative to the current standard practice.