Barzilai University Medical Center

63 Research Day 2020 Barzilai University Medical Center 43 CAN WE IMPROVE THE PERFORMANCE OF CEREBRO- PLACENTAL RATIO AS A PREDICTOR FOR ADVERSE PREGNANCY OUTCOMES BY USING LOCAL REFERENCE RANGES? Leonti Grin, Mark Rabinovich, Simon Shenhav, Eyal Anteby, Efraim Zohav Department of Obstetrics and Gynecology, Barzilai University Medical Center Faculty of Health Sciences, Ben-Gurion University of the Negev, Israel Background The Cerebroplacental ratio (CPR) has been suggested as the most efficient vascular index for the detection of early fetal blood flow redistribution patterns, and adverse obstetric and perinatal outcomes. Consequently, CPR reference range calculators were published in an attempt to improve prediction value in fetuses at risk for adverse intrapartum fetal distress and poor outcome. Hypothesis Local CPR reference curves might have a higher predictive accuracy for adverse pregnancy outcomes than international references curves. Objectives We compared the accuracy of Cerebroplacental ratio (CPR) as a predictor for mode of delivery during the third trimester of pregnancy by applying local versus external CPR reference ranges in low-risk pregnancies Results The study group included healthy singleton pregnancies from 32-week gestation, with an examination- to-delivery interval of <31 days. The three models compared two thresholds: <5th percentile (CPR 1, CPR 3) and <10th percentile (CPR2). The CPR1 and CPR2 models both use local CPR reference ranges, while the CPR3 model uses an external CPR reference range. The main outcome was predictive accuracy for urgent cesarean delivery (CD), operative delivery (OD), and composite outcome (CO), defined as an Apgar score of <7, fetal blood pH < 7.1 or admission to the neonatal intensive care unit (NICU). Overall, 410 low-risk pregnancies with normal weight fetuses were enrolled in the study. All three CPR models turned out to be significant predictors of CD. All the three models were also found to be predictors of OD, and an OR. The positive predictive values (PPV) for CD and OD were both 50% for CPR1, versus 28% and 26% in CPR2, and 24% and 25% in CPR3. Conclusions Classification criteria based on local CPR value <5th percentile to classify CPR as pathological showed the highest PPV for CD and OD. The calculation of local references for CPR should be encouraged.