Objective: 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).
Study Design: 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.
Results: 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%).
Conclusions: The incidence of placental lesions was comparable among term SGA regardless of whether isolated or not and significantly higher than among AGA newborns.
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