Prediction of acidemia at birth by Doppler assessment of fetal cerebral transverse sinus in pregnancies with placental insufficiency.

Abstract

To evaluate the prediction of acidemia at birth using cerebral transverse sinus (CTS) Doppler velocimetry and to determine the best parameter and cut-off values for its prediction in pregnancies complicated with placental insufficiency. This was a prospective cross-sectional study involving 69 pregnant women (26-40 weeks' gestation) with placental insufficiency managed in two Brazilian hospitals. Doppler assessment of the CTS was carried out in the last 24 h before delivery, and the peak ventricular systolic (S-wave) and diastolic (D-wave) velocities as well as the atrial systolic velocity (A-wave) were recorded and the pulsatility index for veins (PIV) was calculated. At birth, arterial and venous umbilical cord blood samples were collected to determine acid-base and pH status. A receiver-operating characteristics (ROC) curve was constructed for each Doppler parameter with birth acidemia as the dependent variable. Sensitivity, specificity, positive and negative predictive values, accuracy and false-positive and false-negative rates were calculated for the parameters considered to be good predictors of acidemia. The S, D and A peak velocities and the S/A ratio were not good predictors of acidemia at birth. The PIV and the (S - A)/S ratio were good predictors of acidemia (area under the ROC curve = 0.698 (P = 0.009) and 0.654 (P = 0.009), respectively). The cut-off values were PIV = 0.855 and (S - A)/S = 0.703). The PIV and the (S - A)/S ratio of the CTS were good predictors of acidemia at birth in this high-risk population with placental insufficiency.