Acute reversible placental dysfunction and abnormal fetal heart rate at delivery

Acute placental dysfunction induced by malaria is characterized by umbilical artery resistance increase and cerebral artery resistance decrease during the crisis. The objective was to evaluate the sensitivity and specificity of fetal Doppler indices and crisis duration for predicting abnormal fetal heart rate (aFHR) at delivery several weeks after the crisis. Method: Every day during the crisis, the umbilical and cerebral resistance indices were measured by Doppler. These indices allowed evaluation of the amplitude of the fetal flow redistribution (C/U = cerebral resistance/umbilical resistance ratio), the duration of the flow redistribution period (i.e. crisis duration) and the Hypoxic index (HI) (mean %C/U change × crisis duration). Results: Population: 46 pregnancies. Mean duration of the flow redistribution period 8±3.2 days, mean C/U change −9%±6; Hypoxic index −86±75; prematures 48%; aFHR 30%). Hypoxic index >150 predicted occurrence of aFHR with high sensitivity and specificity (83%/88%). The presence of abnormal flow distribution (C/U<1.1) and the duration of the period with flow disturbance (>8 days) predicted aFHR at delivery with a sensitivity of 45 and 48% and a specificity of 82 and 84%. Conclusion: The Hypoxic index was more predictive of aFHR at delivery than the amplitude or the duration of the fetal flow redistribution triggered by placental insufficiency.