| Spontaneous fetal behaviours and auditory processing were compared in small for gestational age (SGA) fetuses (n = 15), to appropriate for gestational age (AGA) fetuses (n = 19) from 33 weeks gestational age. Spontaneous fetal heart rate (FHR), body and breathing movements, and muscle tone were observed and an estimate of amniotic fluid was made. Each fetus received a 2 min recording of their mother and a female stranger (counterbalanced over participants) reading a passage while FHR was recorded and body movements were observed. Data analysis showed that there were fewer spontaneous body movements in the SGA fetuses compared to the AGA fetuses. As well, SGA fetuses had less amniotic fluid volume, although it was still with in the normal range. Differential behaviour was seen following the offset of the mother's voice, when it was presented first. The AGA fetuses demonstrated a FHR acceleration in the post-voice period, while the SGA fetuses did not. Women in the SGA group were less educated, gained less weight during pregnancy, and had a lower systolic blood pressure. Newborn outcome data showed that the birth weight, head circumference and length were all less in the SGA group than the AGA group. The findings suggest that SGA fetuses have atypical spontaneous and auditory processing after 33 weeks gestation. Whether these differences are a result of fundamental changes in neurodevelopment has yet to be determined. |
