Is accuracy of estimated fetal weight improved by better image quality scores?

To assess in a group of ultrasound operators of various levels of experience the predictive value of systematic quality scoring to assess estimated fetal weight (EFW) validity.

Screenshots, sonographer experience, and neonate birth weight were collected for 131 ultrasound examinations in the 7 days before birth. The difference (EFW error) between projected birth weight (EFW + [30 g × interval in days to birth]) and actual birth weight was then assessed (absolute value). Three senior sonographers rated all the screenshots (International Society of Ultrasound in Obstetrics and Gynecology 16-point score for image quality) and interobserver reproducibility was assessed concomitantly. The impact of the score on EFW accuracy was then assessed (univariate analysis). Receiver operating characteristic curves allowed us to assess the score's positive predictive value (PPV) for accurate EFW.

Mean birth weight was 2998 ± 954 g and mean EFW error was 8.6% ± 7.1%. Both the sonographer's experience and score significantly impacted the EFW error (P < 0.05). The PPVs of systematic image scores for identifying an EFW error greater than 10% and greater than 15% were appropriate for clinical use (areas under the curve 0.61 and 0.70, respectively). Score reproducibility was modest.

Low image scores and limited ultrasound expertise are associated with an increased risk of inaccurate EFW.