EP01.58: Which maternal and pregnancy characteristics affect obstetric ultrasound quality?

This study aimed to evaluate the maternal and pregnancy characteristics that may impact the quality of obstetric ultrasound assessment at 18-weeks. This retrospective cross-sectional study was conducted at a single centre and included 187 consecutive 18-week scans, 205 fetuses, and 565 ultrasound images. Scans were performed from January 2019 to December 2021 by a single operator using a General Electric Medical Systems ultrasound machine (Zipf, Austria) and an RM6C 2–7-MHz curved array transducer with the same ultrasound settings. Two contrast-to-noise ratios (CNR) per image (six per fetus) were determined using two regions of interest for small (umbilical vein, aorta, and spine) and large anatomical structures (abdominal skin-amniotic fluid, right atria-lung, and sacrum skin-amniotic fluid interface). Based on the two sonographers mean, the CNR was classified as poor (CNR < .75), fair (CNR: .75÷1.5), good (CNR: 1.5÷2.25) and excellent (CNR >2.25). Scans were deemed unsatisfactory if they had at least one poor CNR, and considered good if they had more than three CNRs rated as good or excellent, and acceptable otherwise. Half of the unsatisfactory scans were in obese patients (P = .001), and 9 of 10 patients with obesity class II and III had an unsatisfactory exam (P = .001). Maternal obesity was the main factor affecting fetal ultrasound quality. Unsatisfactory (n = 73) Acceptable (n = 42) Good (n = 72)