OBJECTIVE: To study the Doppler velocimetry of the fetal middle cerebral artery in pregnancies complicated by placental insufficiency, and to verify its role in the prognosis of neonatal survival. METHODS: This was a prospective study of 93 pregnant women with diagnosis of placental insufficiency detected before the 34th week of pregnancy. Placental insufficiency was characterized by abnormal umbilical artery (UA) Doppler (> 95th percentile). The following parameterswere analyzed: umbilical artery (UA) pulsatility index (PI); middle cerebral artery (MCA) PI; brain-placenta ratio - BPR (MCA-PI/UA-PI); MCA peak systolic velocity (MCA-PSV); and PI for veins (PIV) of ductus venosus (DV). The parameters were analyzed in terms of absolute values, z-scores (standard deviations from the mean), or multiples of the median (MoM). The outcome investigatedwas neonatal death during the hospitalization period after birth. RESULTS: Of the 93 pregnancies analyzed, there were 25 (26.9%) neonatal deaths. The group that died, when compared to the survival group, presented a significant association with the diagnosis of absent or reversed end-diastolic flow (88% vs. 23.6%, p < 0.001), with a higher median of UA PI (2.9 vs. 1.7, p < 0.001) and UA PI z-score (10.4 vs. 4.9, p < 0.001); higher MCAPSV MoM (1.4 vs. 1.1, p = 0.012); lower BPR (0.4 vs. 0.7, p < 0.001); higher PIV-DV (1.2 vs. 0.8, p < 0.001) and DV z-score (3.6 vs. 0.6, p < 0.001). In the logistic regression, the independent variables predictive of neonatal death were: gestational age at birth (OR = 0.45; 95% CI: 0.3 to 0.7; p < 0.001) and UA PI z-score (OR = 1.14, 95% CI: 1.0 to 1.3, p = 0.046). CONCLUSION: Despite the association verified by the univariate analysis between neonatal death and the parameters of fetal cerebral Doppler velocimetry, the multivariate analysis identified prematurity and degree of insufficiency of placental circulation as independent factors related to neonatal death in pregnancies complicated by placental insufficiency.
Placental insufficiency; Ultrasonography; Doppler; Fetal hypoxia; Umbilical cord; Middle cerebral artery; Umbilical arteries
