749: Identification of neonates with hypoxic-ischemic encephalopathy (HIE) using debt-time, a measure of intrapartum electronic fetal heart rate (FHR) decelerations

women delivering infants with birthweight 10%ile (IUGR) and those delivering AGA infants. EFM patterns were extracted by trained obstetric research nurses, blind to clinical outcomes, using 2008 NICHD standard. A secondary analysis was performed, comparing IUGR to AGA among only those apparently normal infants, excluding those with composite morbidity: arterial cord pH 7.20, 5 minute Apgar 7, NICU admission. Relative risks and ARs were calculated. Logistic regression was used to adjust for BMI, race, nulliparity, induction, and protracted labor. RESULTS: Of 5,388 infants, 652 (12.1%) were IUGR. IUGR did not confer an increase in risk of minimal variability or bradycardia, but was associated with a decrease in risk of tachycardia (aOR 0.67, 95% CI 0.50, 0.90). IUGR compared to AGA infants were less likely to have accelerations (29.0% v. 35.9%, p 0.01), remaining true even among apparently normal infants (29.0% v. 36.4%, p 0.01). IUGR was associated with more decelerations; a 6% increased risk of late decelerations was attributable to IUGR (AR 0.06, 95% CI 0.02, 0.10), even in apparently normal infants. CONCLUSION: Growth restriction at term confers an increased risk of late decelerations, even in the absence of neonatal morbidity. EFM patterns may require different interpretations based on a priori risk and clinical factors.