Doppler velocimetry of the fetal middle cerebral artery and other parameters of fetal well-being in neonatal survival during pregnancies with placental insufficiency.

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 34(th) week of pregnancy. Placental insufficiency was characterized by abnormal umbilical artery (UA) Doppler (> 95(th) percentile). The following parameters were 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 investigated was 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 MCA-PSV 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.