Consequences of reduced umbilical and increased foetal cerebral flow during malaria crisis on foetal behaviour.

The objectives of this study were (a) to evaluate the sensitivity and specificity of foetal Doppler indices for the prediction of abnormal foetal heart rate (aFHR) at delivery after malaria crisis and (b) to test Doppler parameters against crisis duration for predicting aFHR. Every day during the malaria crisis, the umbilical and cerebral vascular resistance indices were measured by Doppler. These indices allowed evaluation of the amplitude of the foetal flow redistribution induced by malaria (C/U=cerebral resistance/umbilical resistance ratio), the duration of the flow redistribution period and the hypoxic index (mean %C/U change x crisis duration). It was found that the mean duration of the flow redistribution period was: 7 +/- 2 days, mean C/U change -7% +/- 4, hypoxic index -56 +/- 37, prematures 35%, and aFHR 17%. An hypoxic index > 150 predicted occurrence of aFHR with high sensitivity and specificity (100%/91%). The highest foetal flow disturbance (max %C/U) and the duration of the period with flow disturbance (> 7 days) predicted aFHR at delivery with a sensitivity of 10% and 40% and a specificity of 77% and 78%. It was concluded that the hypoxic index was more predictive of aFHR at delivery than the amplitude or the duration (i.e. crisis duration) of the foetal flow redistribution.