Placental abnormalities differ in small for gestational age neonates in relation to their prenatal sonographic abdominal circumference measurements.

Background: Antenatal detection of abdominal circumference (AC) <10th percentile, among small for gestational age (SGA) neonates, probably reflects the severity of their growth restriction. We aimed to study neonatal outcome and placental pathology among SGA neonates in correlation to their AC measurements.Methods: Maternal and neonatal computerized medical records and placental histopathology reports of all SGA neonates, (neonatal birth-weight ≤10th percentile), born between 24 and 42 weeks, during 2015-2018 were reviewed. Included cases with fetal biometric measurements conducted up to 7 days prior labor. Results were compared between cases with sonographic antenatal AC <10th percentile and neonates with sonographic antenatal AC ≥10th percentile. Placental lesions were classified according to "Amsterdam" Placental workshop criteria.Results: The AC <10th percentile group (n = 148) was characterized by higher rate of nulliparity (p = .003), and induction of labor (p = .009), as compared to the AC ≥10th percentile group (n = 41). There were no between groups differences in the rate of maternal BMI (kg/m2), hypertensive disorders, diabetes or smoking. Neonatal hypoglycemia was more common in the AC <10th percentile group as compared to the AC ≥10th percentile group (p = .04). Placentas from the AC <10th percentile group were smaller (p < .001), with more MVM lesions (p = .02) and chronic villitis (p = .04). By multivariate regression analysis, AC <10th percentile and maternal hypertensive disorders, were found to be independently associated with placental MVM lesions, aOR = 2.43 (95% CI 1.04, 5.88) and aOR = 3.15 (95% CI 1.06, 9.31), respectively.Conclusions: Higher rate of placental maternal malperfusion lesions, chronic villitis, and more neonatal hypoglycemia characterize SGA neonates with AC <10th percentile, pointing to the importance of AC measurement as an indicator for placental insufficiency.