286: Is neonatal asphyxia predictable?

Abstract

Most cases of neonatal encephalopathy (NE) in term infants are caused by asphyxia and are preceded by ante- or intra-partum risk factors. The role of FHR rate monitoring is controversial. We evaluated how many cases of asphyxia and NE occur in low risk pregnancies. Prospective observational cohort study in a network of 4 hospitals with shared protocols of intrapartum and neonatal care. One Hub center has NICU and offers therapeutic hypothermia. Fetal heart rate (FHR) monitoring was classified according to ACOG and managed using Clark’s algorithm. Umbilical artery (UA) pH was routinely determined. All neonates from July 2014 to June 2016, born at >35 wks, >1800 g, without lethal malformations and with consenting parents were included. Neonatal asphyxia was defined as pH ≤7.0 or BE ≤-12 mMol/L in UA or within 1 h, 10 min Apgar <5, need for resuscitation >10 min. Asphyxiated neonate were monitored with Thomson score. NE was classified according to Sarnat&Sarnat and II-III grades underwent hypothermia. Data regarding pregnancy, delivery, sentinel events, neonatal outcome were collected. Pregnancies were assigned to: low risk (no risk factors), antepartum risk (maternal age >40 years, BMI >30, oligo or polihydramnios, FGR, induction of labor, maternal disease, previous cesarean), intrapartum risk (sentinel event, meconium grade 2-3, fever, tachysystole), both ante and intrapartum risk. Neonatal asphyxia occurred in 21.5‰ cases (321/14,896) and 278 fulfilled the study criteria. Rate of cesarean delivery was 19.8%, of which 70.9% for non-reassuring fetal status. Rate of vacuum delivery was 23.7%. NE occurred in 14/278 (5%) and 10 cases received hypothermia. No NE occurred in neonates not enrolled. The figure shows numbers and severity of NE cases in asphyxiated neonates according to presence of risk factors. Sentinel events occurred in 67/278 asphyxia cases (24%) and in 6/14 (43%) NE cases. ACOG FHR cat. II or III occurred in 140/278 (50.4%) and preceded NE in 9/14 (64%). 115/278 (41.4%) cases of asphyxia and 2/14 (14.3%) cases of NE were not preceded by sentinel events or abnormal CTG. 41.4% cases of asphyxia and 14.3% cases of NE were not preceded by sentinel events or abnormal CTG. 16.2% of asphyxiated and 3/14 (21.4%) NE occurred in low risk pregnancies.