Assessment of late on-set fetal growth restriction using SMI (superb microvascular imaging) Doppler.

Background: The identification of late-onset fetal growth restriction (FGR) fetuses remains a challenge, given the difficulty to distinguish them from healthy small for gestational age (SGA) fetuses. Given the limitations of conventional Doppler for the identification of placental insufficiency, the appearance of superb microvascular imaging (SMI) Doppler seems promising. Our main objective was to evaluate the diagnostic capability of SMI Doppler for the detection of placental insufficiency findings.

Methods: A prospective observational study was conducted at a tertiary care center, including 51 patients who had been diagnosed with late on-set SGA or FGR. A placental ultrasonographic evaluation was carried out using SMI Doppler. Patients were sorted into two groups attending to the histologic evaluation of the placentas after delivery: Group 1 (21 cases), Normal group; and Group 2 (30 cases), FGR group.

Results: Placentas in the FGR group had lower peak systolic velocity (PV) values of the chorionic plate. The PV of the other vessels were consistently lower in the FGR group that in the normal group, although without reaching statistical significance.

Conclusions: The PV of the chorionic plate measured with SMI Doppler, have the capacity to identify placental insufficiency findings. Ultrasonographic placental assessment using SMI Doppler appears to be a useful technique for the evaluation of suspected late on-set placental insufficiency.