Fetal circulation and malaria

OBJECTIVE: To quantity the fetal vascular changes during flare-up, and to evaluate the sensitivity and the specificity of Doppler indices for the prediction of acute fetal distress at the end of the pregnancy. METHOD: Every day of flare-up the umbilical resistance (Rp), cerebral resistance (Rc), cerebro-placental ratio (CPR = Rc/Rp), and hypoxia index (HI = delta % CPR x crisis duration) were calculated. RESULTS: Twenty-three pregnancies were investigated at St Laurent du Maroni Hospital (French Guiana). During flare-ups the Doppler placental resistance increased (placental disorder), cerebral resistance decreased (vasodilation), CPR decreased (flow redistribution toward the brain), and HI increased. An abnormal CPR (< 1) was associated with abnormal fetal heart rate (FHR) in 61.5% of the cases, a CPR > 1 was associated with a normal FHR in 80% of the cases. (sensitivity: 80%, specificity 61%). A CPR < 1 was associated with one of the abnormalities (abnormal FHR, cesarean section, abnormal Apgar) in 71% of the cases, a CPR > 1 was associated with normal delivery in 55% of the cases (sensitivity: 71.4%, Specificity 55%). A HI higher than 150 was associated with abnormal FHR in 75% of the cases, a HI < 150 was associated with normal FHR in 90% of the cases (sensitivity: 89%, specificity: 77%). Lastly the combination (HI > 150 + CPR < 1) was associated with abnormal FHR in 80% of the cases, 1 or 2 of these parameters were associated with normal FHR in 84.6% of the cases (sensitivity: 80%, specificity: 84%). The minimum CPR and the HI during malaria flare-up can be used to predict acute fetal distress at delivery.