Perinatal outcomes and placental histology in small-for-gestational-age pregnancies-A comparison of population-based and universal growth charts

Objective To assess obstetric, perinatal, and placental histologic findings in small-for-gestational-age (SGA) neonates according to different growth charts. Methods A retrospective cohort of singleton deliveries from 2008 to 2019 were divided into SGA neonates according to the local population-based chart, SGA according to universal standard growth charts (but appropriate for gestational age [AGA] according to local charts) and AGA deliveries according to both charts. Results A total of 626 local population SGA deliveries, 132 universal SGA and 468 AGA deliveries were compared. The local population SGA group had a significantly higher rate of preterm and cesarean deliveries. An adverse neonatal outcome occurred in 27.2% of the local population SGA group, 9.8% of the universal SGA group and 6.7% of the AGA group (P < 0.001). In the local population SGA group, placental weight was lower, birth weight to placental weight ratio was highest, and the rate of maternal malperfusion lesions was highest-55.4% versus 45.4% in the universal SGA group and 39.1% in the AGA group (P < 0.001). Villitis of unknown etiology was significantly more common and histologic chorioamnionitis was significantly less common in the local population SGA group. Conclusions Our findings support the use of a local population-based growth chart for the diagnosis of fetal growth restriction.