Placental fibronectin staining is unaffected in pregnancies complicated by late‐onset intrauterine growth restriction and small for gestational age fetuses

OBJECTIVE: To investigate the placental staining pattern of fibronectin, an extracellular matrix protein essential for trophoblastic invasion, in pre-eclampsia and fetal growth restriction. METHODS: This was a retrospective study conducted at the University of Udine, including the placentas of women with pre-eclampsia and fetal growth restriction collected between January 1, 2001, and December 31, 2010. Fibronectin was evaluated in placental tissue micro-array by immunohistochemistry, describing localization and intensity of staining. RESULTS: The study included the placentas of 36 women with early-onset (delivery <34 weeks of gestation) pre-eclampsia; 6 with early-onset HELLP syndrome; 17 with early-onset intrauterine growth restriction (IUGR); 14 with late-onset (delivery ≥34 weeks of gestation) pre-eclampsia; 35 with late-onset IUGR; 18 with small for gestational age (SGA) fetuses (birth weight <10th percentile); and 64 controls. Fibronectin was present both at the cell surface and in the cytoplasm. Cytoplasm staining intensity resulted higher in early forms of pregnancy-related complications compared to controls, although this was statistically significant (P<0.05) only for early-onset pre-eclampsia (P=0.085 for HELLP syndrome; P=0.091 for IUGR). Also, late-onset forms of pre-eclampsia had stronger cytoplasmic and pericellular staining compared to controls (P<0.05). Interestingly, staining of both late-onset IUGR and SGA was comparable to controls. CONCLUSION: Fibronectin appeared to be unaffected in women with late-onset IUGR and SGA fetuses, suggesting a peculiar common pathogenetic pattern in these conditions.