163: Electronic fetal monitoring (EFM) patterns in the second stage of labor: association and test characteristics for fetal acidemia

in the second stage of labor: association and test characteristics for fetal acidemia Alison G. Cahill, Anthony Odibo, Kimberly Roehl, George Macones Washington University in St. Louis, Department of Obstetrics and Gynecology, St. Louis, MO OBJECTIVE: To estimate the association and screening efficacy of EFM patterns prior to delivery and acidemia using NICHD Categories and definitions. STUDY DESIGN: We conducted a 5-year retrospective cohort study of all singleton, non-anomalous gestations delivered at 37 weeks from the second stage of labor. The primary exposure was 30 minutes of EFM immediately prior to delivery, interpreted by 2 dedicated obstetric research nurses, formally trained and re-trained in EFM interpretation, blind to clinical and outcome data. EFM patterns were interpreted using the NICHD nomenclature, including the 3-Category system and feature definitions. EFM was interpreted in 10-minute epochs, and then overall. The primary outcome was acidemia, defined as an umbilical cord gas pH 7.10. Relative risks and 95% confidence intervals, and test characteristics for acidemia were calculated. RESULTS: Of 5,388 patients meeting inclusion criteria, 98.9% (5331) had a pH 7.10 and 1.1% (57) were acidemic. In bivariate analyses of the EFM patterns 30 minutes prior to delivery, baseline tachycardia (RR 3.3, 1.7 6.3) was the only pattern among NICHD-defined EFM Categories or features associated with acidemia; Categories IIII, minimal variability (RR 0.7, 0.3–1.6), marked variability (RR 2.2, 1.0 4.6), repetitive late (RR 1.3, 0.5–3.4) and prolonged decelerations (RR 3.1, 1.2– 8.2) all demonstrated no association. Test characteristics for each EFM Category or features were equally poor (Table). CONCLUSION: The NICHD 3-tiered Category system, as well as specifically defined features such as variability and deceleration types, demonstrate weak or no association with acidemia and do not demonstrate clinically useful test properties for EFM interpretation in the second stage. 164 Glial fibrillary acidic protein as a serum biomarker for the early identification of neonatal periventricular white matter injury in preterm neonates Amanda Stewart, Jacky Jennings, Aylin Tekes, Huisman Thierry, Frances Northington, William Savage, Allen Everett, Ernest Graham Johns Hopkins University School of Medicine, Gynecology and Obstetrics, Division of Maternal-Fetal Medicine, Baltimore, MD, John Hopkins University School of Medicine, Pediatrics, Baltimore, MD, Johns Hopkins University School of Medicine, Pediatric Neuro-Radiology, Baltimore, MD, Johns Hopkins University School of Medicine, Pediatrics, Baltimore, MD, Johns Hopkins University School of Medicine, Pathology-Transfusion Medicine, Baltimore, MD, Johns Hopkins University School of Medicine, Pediatric Cardiology, Baltimore, MD OBJECTIVE: Periventricular white matter injury(PWMI) in preterm infants results in cerebral palsy in 60-100% of survivors. Glial fibrillary acidic protein(GFAP), an abundant white matter protein localized to astrocytes, is normally undetectable in serum and only measureable after CNS injury. We sought to determine if serum GFAP levels can be used to identify neonates developing PWMI. STUDY DESIGN: This is a case control study of all neonates born at a single tertiary care hospital from 4/09 4/11 at 2334 weeks gestation diagnosed with PWMI on a head ultrasound at 6 weeks of life. Each case with PWMI was gestational age matched to a subsequent neonate with a normal head ultrasound. GFAP was measured in cord blood at the time of birth, at NICU admission, and on days 1-4 of life. Paired variables were compared using paired t-tests and McNemar chi square. Wilcoxon rank sum tests were used to compare GFAP levels. RESULTS: During this 2 year period, 21 cases with PWMI occurred. Cases and controls did not differ in birthweight (1077 / 544 grams, 963 / 492 grams) or incidence of cesarean delivery (61.9%, 66.7%). Cases with PWMI had a significantly increased incidence of intraventricular hemorrhage (90.5%, 23.8%, p 0.001), 5 min Apgar 7 (66.7%, 23.8%, p 0.01) and seizures (42.9%, 0%, p 0.004). There was no significant difference in umbilical arterial pH (7.22 /1 0.19, 7.27 / 0.06), or base deficit (4.4 / 6.8, 2.6 / 1.7). GFAP was not significantly different in cord blood, at NICU admission, or day 1, but was significantly increased at days 2-4 of life (p 0.002, 0.0005, 0.04). The 6 cases with cystic PWMI had significantly elevated GFAP levels compared to other cases (p 0.03). Logistic regression of GFAP at day 4 of life showed sensitivity 50%, specificity 78.6%, PPV 75% and NPV 55% in identifying PWMI. CONCLUSION: Serum GFAP levels were significantly elevated on day of life 2-4 in neonates diagnosed with PWMI at 6 weeks. Measurement of GFAP in the perinatal period provides a rapid quantitative way to diagnose white matter injury, and may also correlate with the scale of injury and neurocognitive outcomes. Poster Session I Clinical Obstetrics, Medical-Surgical-Disease, Neonatology, Physiology-Endocrinology www.AJOG.org