engleski

Doppler monitoring of the fetal brain response to chronic hypoxia

Objective: To study the cerebral and umbilical hemodynamics changes in growth-retarded fetuses with chronic hypoxia and to determine if at long term, fetal brain hyperfusion with loss of cerebral vascular flow velocity variability is associated with poor fetal outcome and brain damage. Study Design: The cerebral and umbilical hemodynamics was assessed by Doppler in 5 growth-retarded and hypoxic fetuses, mainly every day during 11 to 21 days. The evolution of the fetal hemodynamics was interpreted according to the clinical, anatomical and histological findings. Results: All 5 fetuses had poor fetal outcome including fetal death at delivery (n=2), neonatal intensive assistance (n=3) followed by fetal death for 2 of them. Fetal flow redistribution with brain hyperperfusion was present in all 5 fetuses during the whole period of observation. The fetal deterioration was characterized by: (1) the progressive development of oligohydramnios; (2) the disappearance of the cerebral flow velocity variability during the early phase of deterioration; (3) the occurrence of fetal heart rate decelerations; and finally (4) the increase of cerebral vascular resistances with reduction of brain perfusion during the later phase of deterioration. The histology of two brains revealed hypoxic lesions. Conclusion: The decrease in cerebral-umbilical ratio (mean 30 to 40 %) during 11 to 21 days, which correspond to a sustained hypoxia with increased brain perfusion, and the loss of cerebral flow variability were associated in all severe fetal outcome with high risk of death.

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