Do placental lesions among term small for gestational age newborns differ according to the clinical presentation?

To examine the incidence of placental lesions among women who delivered isolated small for gestational age newborns (isolated-SGA) at term compared to placentas from non-isolated-SGA born at term, early SGA and appropriate for age newborns (AGA).

A case-control study conducted at a university teaching hospital. Placentas of women who delivered a newborn with a birthweight less than the 10th percentile were included. Group A (study group): isolated-SGA delivered at term. Group B (1st control group): Term SGA accompanied antepartum with oligohydramnios or maternal hypertension (non-isolated-SGA). Group C (2nd control group): early SGA delivered before 34 weeks. Group D (3rd control group): placentas of low risk women who delivered AGA newborns at term. A total of 307 placentas were included: 72, 81, 60 and 94 placentas from Groups A, B, C, and D respectively. The primary outcome was the incidence of placental lesions that characterize SGA.

The most frequent placental lesion found among all groups was maternal obstructive lesions, which appeared in 45.8% and 45.7% of placentas from groups A and B respectively (p=0.98). The incidence among group A was significantly higher than in group D (20.2%) (p=0.0006) and lower than in group C (76.7%) (p=0.0004). The incidence of any placental lesion that characterized SGA among group A (69.4%) was 7.9 times higher than in group D (22.3%) (p<0.0001) and comparable to group B (61.7%) (p=0.3). The incidence of any placental lesion was highest among group C (83.3%).

The incidence of placental lesions was comparable among term SGA regardless of whether isolated or not and significantly higher than among AGA newborns.