Placental mapping of patients with birth weights below the third percentile

BACKGROUND: Fetal growth restriction (FGR) is a frequent diagnosis with multiple etiologies (maternal, fetal, environmental) for which the placenta can be involved. A postnatal etiological work-up, such as placental pathology analysis, can help to identify the etiology of FGR and implement measures to prevent recurrence in a subsequent pregnancy. OBJECTIVE: The aim of this study is to unravel and provide an update on the mapping of possible placental lesions in the context of hypotrophic birth (below the third percentile). METHOD: This is a single-center retrospective observational cohort study, in a tertiary care maternity (Antoine Béclère Hospital, Clamart, France). Inclusion criteria were: singleton pregnancy, live-born neonate, delivery between January 2014 and December 2018, birthweight below the 3rd percentile according to Audipog curves. Data from placental anatomopathological analysis were collected and analyzed using Amsterdam criteria. RESULTS: Among 733 eligible pregnancies, 585 placentas (79.8%) underwent pathological examination. At least one lesion of maternal vascular malperfusion (MVM) was identified in 75.6% of cases. The most frequent findings were placental hypoplasia (64.6%), accelerated villous maturation (18.5%), and placental infarctions (12.5%). A progressive decrease in birth weight was observed with increasing numbers of MVM criteria. CONCLUSION: MVM lesions are highly prevalent in severe neonatal hypotrophy and correlate with disease severity. Placental pathological examination is a key component of the etiological work-up of FGR and may guide management and preventive strategies in subsequent pregnancies.