We evaluated the impact of chorioamnionitis on the intrapartal EEG delta frequency in the non-anesthetized preterm sheep. 10 mg intra-amniotic LPS or saline were given 2 or 14 days before preterm birth at gestational day 125. Lambs were delivered by Caesarean section under local anesthesia. A 5-minute EEG depicted delta activity and amplitude, and the relationship between EEG delta activity and both the white matter (WM) and cortical microglial activation and apoptosis was analyzed. EEG delta activity was increased significantly in the 14-day LPS preterm fetuses compared to both preterm control and 2-day LPS animals (p less than 0.05). No differences were seen between controls and the 2-day LPS fetuses. A direct association was demonstrated between EEG delta activity and both cortical microglial activation (r = 0,645, p = 0,024) and apoptosis (r = 0,580, p = 0,048), and between delta and WM activated microglia (r = 0,742, p = 0,006) and apoptosis (r = 0,777, p = 0,003). This study is the first to show a relationship between brain dysfunction and chorioamnionitis-related injury at birth.