OC14.02: Prediction of small‐for‐gestational‐age neonates at 35–37 weeks

This study aimed to evaluate the performance of sonographic biometric and Doppler parameters assessed at a routine third trimester scan, in combination with maternal characteristics, in predicting small-for-gestational-age (SGA) neonates and adverse perinatal outcomes. This was a cohort study of low-risk singleton pregnancies undergoing routine ultrasound between 35+0 and 37+6 weeks. Demographic characteristics, estimated fetal weight (EFW) and abdominal circumference (AC) centiles, and Doppler indices, including the Pulsatility Index (PI) of the Umbilical Artery (UA), Middle Cerebral Artery (MCA), and Uterine Artery (UtA) were evaluated. The Cerebroplacental ratio (CPR) was calculated, all indices were converted into Multiples of the Median (MoM). Multivariable logistic regression analysis was performed. Receiver-operating curves (ROC) were created to determine factors predictive of an SGA neonate with birthweights <3rd, 5th, and 10th centile and composite adverse perinatal outcomes (CAPO), which was comprised of intrauterine death, neonatal death, and neonatal intensive care unit admission. A total of 14,161 pregnancies were included. EFW centile (adjusted odds ratio (aOR) 0.91 (95% CI, 0.9-0.92), p < 0.001) (aOR 0.9 (95% CI, 0.89-0.91), p < 0.001), UA PI (aOR 4.6 (95% CI, 2.2-9.6), p < 0.001) (aOR 2.5 (95% CI, 1.1-6.1), p < 0.04), MCA PI (aOR 0.37 (95% CI, 0.2-0.7), p = 0.002) (aOR 0.26 (95% CI, 0.12-0.59), p = 0.001), CPR (aOR 0.23 (95% CI, 0.13-0.42), p < 0.001) (aOR 0.25 (95% CI, 0.12-0.53), p < 0.001), and UtA PI (aOR 2.5 (95% CI, 1.68-3.83), p < 0.001) (aOR 2.2 (95% CI, 1.31-3.6), p = 0.003) were independent predictors of SGA <5th and SGA <3rd or SGA with CAPO, respectively. The combination of EFW, CPR, and UtA PI was associated with an Area under the curve (AUC) of 0.93 (95% CI 0.92-0.94), p < 0.001 for both outcomes. In an unselected population, the UA PI, MCA PI, CPR, and UtA PI are independent predictors of SGA and adverse perinatal outcomes. The combination of these parameters can reliably predict SGA and adverse perinatal outcomes with a high degree of accuracy.