Fetal flow redistribution to the brain in response to malaria infection: does protection of the fetus against malaria develop over time?
OBJECTIVE
Malaria during pregnancy induces deterioration of placental function, resulting in transient fetal hypoxia. Our objective was to evaluate the sensitivity and specificity of fetal Doppler indices for prediction of abnormal fetal heart rate at delivery and to compare the amplitude of the fetal vascular response to malaria in 2 groups of fetuses (1994 and 1996) separated by an interval of 2 years.


METHODS
Every day during the crisis, the umbilical and cerebral resistance indices, the cerebral-umbilical resistance ratio, and the hypoxic index (mean percent cerebral-umbilical resistance ratio change x crisis duration) were calculated.


RESULTS
In group 2 (1996), the duration of the flow redistribution period was about 7 days (mean cerebral-umbilical resistance ratio change +/- SD, 7%+/-4%; hypoxic index, 49+/-26; premature, 35%; and abnormal fetal heart rate, 17.5%). A hypoxic index greater than 150 predicted abnormal fetal heart rate with high sensitivity and specificity (group 1, 80% and 85%; and group 2, 100% and 91 %). Moreover, in group 2 (1996), the amplitude of the fetal vascular response and the rate of long-duration crisis were significantly lower than in group 1 (1994; P < .01). Nevertheless, the hypoxic index was much more predictive of fetal heart rate at delivery than the amplitude or duration (i.e., crisis duration) of the flow redistribution.


CONCLUSIONS
The hypoxic index value during the crisis allowed prediction of abnormal fetal heart rate at delivery. In group 2, the absence of a long-term flow redistribution period and the smaller hemodynamic changes (lower hypoxic index) associated with a lower occurrence of abnormal fetal heart rate could be related to improvement of pregnancy management, acquired protection during the interval between the 2 studies, or both.
Arbeille
Philippe
P
Department of Nuclear Medicine and Ultrasound, Institut National de la Santé et de la Recherche Médicale 316, Centre Hospitalier Universitaire Trousseau, Tours, France.
Caries
Gabriel
G
Tobal
Nathalie
N
Herault
Stéphane
S
Georgescus
Monica
M
Bousquet
Frantz
F
Perrotin
Franck
F
D000328:Adult; D001921:Brain / Q000098:blood supply* / Q000196:embryology; D005260:Female; D005311:Fetal Hypoxia / Q000503:physiopathology*; D006340:Heart Rate, Fetal; D006801:Humans; D016778:Malaria, Falciparum / Q000503:physiopathology*; D021041:Placental Circulation / Q000502:physiology; D011237:Predictive Value of Tests; D011247:Pregnancy; D015597:Pregnancy Complications, Parasitic / Q000503:physiopathology*; D012680:Sensitivity and Specificity; D018608:Ultrasonography, Doppler; D016216:Ultrasonography, Prenatal