Pregnancy outcome and placental pathology in small for gestational age neonates in relation to the severity of their growth restriction

Purpose: To investigate neonatal outcome and placental pathology in pregnancies complicated with small for gestational age neonates (SGA), in relation to the severity of growth restriction. Methods: The medical records and placental histology reports of all neonates with a birth-weight (BW) <= 10th percentile, born between 24-42 weeks, during 2010-2015, were reviewed. Placental lesions were classified into maternal and fetal vascular malperfusion (MVM and FVM) lesions. Results were compared between neonates with BW <5th percentile (severe SGA group), neonates with BW between 5th-10th percentile (mild SGA group) and a control group of appropriate for gestational age (AGA) neonates. Composite neonatal outcome was defined as one or more of early complications. Results: Overall, 753 neonates were included, 238 in the severe SGA group, 266 in the mild SGA group, and 249 in the control group. The severe SGA group had higher rates of composite adverse neonatal outcome as compared with the mild SGA and control groups (37.2 versus 17.6%, versus 24.5%, respectively, p < .001). The SGA group was characterized by higher rates of placental MVM and FVM lesions, compared with controls (p < .001 for both). After controlling for confounders, using a multivariate regression analysis, the likelihood of detecting placental MVM and FVM lesions was increased as neonatal birthweight decreased. Conclusions: Worse neonatal outcome and more placental MVM and FVM lesions correlate with the severity of neonatal growth restriction in a "dose-dependent" manner.