Abnormalities of placental development and function are associated with the different fetal growth patterns of hypoplastic left heart syndrome and transposition of the great arteries

Background Birthweight is a critical predictor of congenital heart disease (CHD) surgical outcomes. Hypoplastic left heart syndrome (HLHS) is cyanotic CHD with known fetal growth restriction and placental abnormalities. Transposition of the great arteries (TGA) is cyanotic CHD with normal fetal growth. Comparison of the placenta in these diagnoses may provide insights on the fetal growth abnormality of CHD. Methods Clinical data and placental histology from placentas associated with Transposition of the Great Arteries (TGA) were analyzed for gross pathology, morphology, maturity and vascularity and compared to both control and previously analyzed HLHS placentas [1]. RNA was isolated from HLHS, TGA and control placentas and sequenced by Illumina HiSeq.Gene, analysis was performed using TopHat, R and MSigDB. Cluster analysis was performed using GoElite and Pathway analysis performed using PANTHERdb Overrepresentation Test. Immunohistochemistry was utilized to assess placental nutrient transporter expression in all three groups. Results Placental weight was reduced in TGA cases, and demonstrated reduced villous vasculature, immature terminal villi, and increased fibrin deposition in the parenchyma compared to controls and reflected our previous data from HLHS placentas. However, birth weight was not reduced in TGA cases compared to controls in contrast to the HLHS cohort and birthweight:placental weight ratio was significantly increased in TGA cases but not HLHS compared to control. Need to include RNA and IHC. Conclusions Despite common vascular disturbances in placentas from HLHAs and TGA, these do not account for the