Atypical fetal voice processing in preeclamptic pregnancy.

Objective: To compare fetal heart rate (HR) response to the mother's voice in pregnancies complicated by preeclampsia with those of fetuses in uneventful, normotensive pregnancies. Method: Fifty fetuses (n = 22, preeclampsia; n = 28, uneventful, normotensive pregnancies) between 32 and 40 weeks gestational age were recruited. Each fetus was presented with a 2-min no-sound baseline period followed by a 2-min voice period during which an audio recording of his/her mother reading a story was played through a loud speaker over the maternal abdomen at an average of 95 dBA followed by a 2-min no-voice offset period. HR was recorded continuously. Results: Fetuses in the preeclamptic group showed no response to the mother's voice when it was played. In comparison, fetuses in the uneventful, normotensive group responded to the mother's voice with a HR increase. Conclusion: Fetuses in pregnancies complicated by preeclampsia show atypical auditory processing of the mother's voice. Such atypical responding may reflect a delay in auditory system maturation, functional elevation of sensorineural threshold, or decreased thyroid hormone.