Quantitative evaluation of placental vascularization using MV-Flow imaging for predicting small-for-gestational-age neonates

Objective To evaluate the association between third-trimester placental vascularization measured by microvascular flow (MV-Flow) imaging and the risk of small-for-gestational-age (SGA) neonates.Methods In this prospective cohort study, women with singleton pregnancies at 30–32 weeks’ gestation underwent MV-Flow ultrasound for quantification of placental vascular indices (VI). Maternal characteristics, fetoplacental Doppler parameters, and MV-Flow–derived VI were analyzed, and pregnancy outcomes were recorded.Results Of 207 pregnancies, 20 (9.7%) resulted in SGA neonates and 187 in appropriate-for-gestational-age (AGA) neonates. Compared with the AGA pregnancies, placental VI in the SGA group were significantly lower across the upper, middle, and lower regions of the placenta (upper: 32.0 ± 13.4 vs 43.1 ± 13.8, middle: 36.0 ± 15.3 vs 49.6 ± 15.0, lower: 30.3 ± 10.0 vs 42.5 ± 13.5; all p < 0.001). The SGA group also exhibited higher uterine artery pulsatility index (UtA-PI) and lower middle cerebral artery PI (MCA-PI) and cerebroplacental ratio (CPR) (all p < 0.05). In multivariable logistic regression, UtA-PI, CPR, and mid-placental VI were independently associated with SGA. The middle placental VI demonstrated moderate discriminative for SGA (AUC 0.756) compared with UtA-PI (AUC 0.626) and CPR (AUC 0.695). A combined model incorporating UtA-PI, CPR, and placental VI achieved an AUC of 0.866 with 55% sensitivity and a 10% false-positive rate.Conclusions Reduced placental vascularization index measured by MV-Flow ultrasonography is significantly associated with SGA. Integration of MV-Flow–derived VI with conventional Doppler parameters may improve risk stratification for SGA and provides supportive evidence for the potential clinical value of MV-Flow in assessing placental microcirculation and fetal growth.