P08.12: Fetal middle cerebral artery peak systolic velocity and acidemia at birth in pregnancies complicated by placental dysfunction

Abstract

The aim of this study was to determine the correlation between middle cerebral artery (MCA) peak systolic velocity (PSV) and acidemia at birth in pregnancies complicated by placental dysfunction. The study was performed as a prospective cross-sectional analysis of Doppler measurements in 93 patients with the diagnosis of placental dysfunction by the abnormal umbilical artery (UA) Doppler. Inclusion criteria were: singleton pregnancy, intact membranes, absence of fetal congenital or chromosomal abnormalities. Doppler sonographic exams of the UA, MAC, ductus venosus (DV) and fetal biophysical profile (BPS) were performed every 1 to 3 days. It was analyzed the last assessment obtained right before birth or the antenatal steroids. Acidemia at birth was defined as an umbilical artery pH below 7.20. Statistical analysis included backward logistic regression and stepwise multiple regression. The level of significance was set at P < 0.05. A significant correlation was found between acidemia at birth and abnormal BPS (22.9% vs 15.5%, p = 0.019), UA-PI values (median 2.1 vs 1.7, p = 0.014) and its z-score (median 8.5 vs 5.2, p = 0.004), MCA-PI z-score (median −2.7 vs −2.1, p = 0.042), CPR (median 0.5 vs 0.7, p = 0.005) and its z-score (median −3.3 vs −3.0, p = 0.046) and DV-PIV values (median 1.0 vs 0.8, p = 0.020) and its z-score (median 2.3 vs 0.6, p = 0.019). Regarding the MCA-PSV and acidemia, no significant correlation was observed. After performing logistic regression, the remaining variables were UA-PI z-score and MCA-PI z-score, being 66.7% of cases correctly classified for acidemia. The multiple regression revealed as remaining variables the CPR z-score and DV-PIV z-score, correctly classifying 70.2% of cases with this model. No correlation between MCA-PSV and acidemia at birth was found. This study reinforces that the degree of placental dysfunction and the fetal adaptation capacity are directly related to acidemia at birth.