Placental histopathological correlates of umbilical artery Doppler velocimetry in pregnancies complicated by fetal growth restriction

Objective: The objective of the study was to evaluate the association between placental histological patterns and umbilical artery (UA) Doppler velocimetry in pregnancies complicated by fetal growth restriction (FGR). Methods: A cohort of 126 FGR pregnancies was followed according to a standard protocol. Placental lesions were diagnosed according to consensus nomenclature and standardized criteria. Results: Pulsatility index was normal in 45 (35.7%) and increased in 44 (34.9%) women. End-diastolic UA Doppler flow was absent in 27 (21.4%) and reversed in 10 (7.9%). Fifty-four women (42.9%) had preeclampsia. In preeclampsia, increasing Doppler abnormalities, from normal to reversed UA end-diastolic flow, were directly associated only with an increased number of placental syncytial knots. In normotensive pregnancies, Doppler abnormalities were associated with increased intervillous fibrin deposits, villous hypoplasia, syncytial knots, placental site giant cells, immature intermediate trophoblast, and with pattern of lesions indicating superficial implantation and maternal vascular underperfusion. In the whole cohort, increase of syncytial knots [odds ratio (OR)=28.7; 95% confidence interval (CI)=2.75-298.5], intervillous fibrin deposits (OR=2.1; 95%CI=1.04-4.28), placental site giant cells (OR=3.0; 95%CI=1.05-8.84), and patterns suggesting maternal underperfusion (OR=2.9; 95%CI=1.0-7.1) were independently associated with increased rates of absent/reversed UA end-diastolic flow. Conclusions: In pregnancies complicated by FGR, abnormalities of UA Doppler velocimetry were associated with placental lesions indicating superficial implantation and maternal vascular underperfusion.