Purpose: Doppler flow parameters of fetal umbilical artery (UA) and middle cerebral artery (MCA) have been widely used for fetal growth restriction (FGR), but their diagnostic efficacy remains contentious. The purpose of this study is to clarify the superiority of cerebroplacental ratio (CPR) and umbilicocerebral ratio (UCR) in terms of their correlation and predictive accuracy in diagnosing FGR.

Methods: Doppler flow parameters of the UA and MCA were tested for FGR patients and normal pregnant women during the third trimester. Collection of delivery gestational weeks and neonatal birth weight were conducted. Logistic regression and area under the curve (AUC) analysis were used to elucidate the association and diagnostic accuracy of CPR and UCR for diagnosing FGR.

Results: The CPR-EDV and CPR-MFV in FGR patients were higher, while the CPR-S/D, CPR-PI, and CPR-RI were lower (P<0.05). The UCR-EDV in the FGR group was lower than that in the NC group, while the UCR-S/D and UCR-PI were higher than those in the NC group (P<0.05). Only the CPR-PI (OR:0.166, 95% CI 0.049 ~ 0.563, P = 0.004) was independently associated with FGR. A positive correlation between CPR-PI and delivery gestational weeks was found, as well as neonatal birth weight. The AUC of CPR-PI for detecting FGR was 0.719 (95% CI 0.594 ~ 0.844; P=0.003), with a critical value of 1.57.

Conclusion: Compared with UCR and simple UA or MCA blood flow parameters, CPR-PI may be the most optimized ultrasound parameter for diagnosing and assessing FGR.

Fetal growth restriction, Cerebroplacental ratio, Umbilicocerebral ratio, Middle cerebral artery doppler, Umbilical artery doppler, Blood flow parameters, Obstetric ultrasound, Pregnancy and complications