Fetal behaviour in preeclamptic compared to low-risk normotensive pregnancies

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Dorland, Jaclyn
Fetal behaviour , preeclampsia
Preeclampsia is associated with placental insufficiency and fetal growth restriction. Fetal growth restriction is associated with an increased risk for language deficits at 2-5 years of age. However, fetal auditory processing in pregnancies complicated by preeclampsia has not been examined and is the focus of this study. Spontaneous and auditory elicited fetal behaviours were compared in 40 mother-fetal pairs (n=20 preclamptic and n=20 low-risk normotensive pregnancies) from 33 to 39 weeks gestational age (GA). Spontaneous fetal heart rate, body and breathing movements and muscle tone were observed and an estimate of amniotic fluid was made. To test if the fetuses could hear, six 2.5s trials (3, 110 dB pink noise; 3, no-sound control) were intermixed and randomly presented; fetal heart rate was recorded for 30 s following trial onset and body movements were observed for 5 s. Finally, the mother’s voice recorded reading a children’s story was presented: 2 min of no sound, 2 min of mother’s voice (95 dB A) and 2 min of no sound. Sounds were delivered through a speaker 10cm above the abdomen. During the 6 min procedure, fetal heart rate was recorded continuously and body movements were video recorded. Fetuses in the preeclamptic group were born earlier, t(37)=4.79, p<0.000. There were no differences in birth weight at delivery. Testing showed no differences between groups for any measure of spontaneous behaviour. There was increased heart rate, F(1,36)=37.47, p<0.001, and number of body movements, F(1, 35)=54.04, p<0.001, in response to the pink noise compared no-sound control trials, indicating that both groups could hear external sounds. No differences in fetal heart rate or body movement responses to the playing of the mother’s voice were found between the two groups; although, there was a suggestion that gestational age affected responding. There were no differences found in spontaneous behaviours or auditory processing behaviours in fetuses of pregnancies complicated by mild to moderate preeclampsia compared to those in low-risk, normotensive pregnancies. It is suggested that future studies examining fetal auditory processing in preeclamptic pregnancies employ sufficient sample size for analyses by gestational age at time of testing.
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