Placental Vascular Physiology and Trophoblast Invasion Defects as Determinants of Intrauterine Growth Restriction in Women with Pre-eclampsia in Enugu State, South East Nigeria

Background: Intrauterine growth restriction complicating pre-eclampsia results from defective trophoblast invasion of maternal spiral arteries during early gestation, leading to high-resistance uteroplacental blood flow and chronic foetal hypoxia. The molecular regulators of trophoblast invasion including hypoxia-inducible factor-1 alpha, vascular endothelial growth factor, and matrix metalloproteinases have been primarily characterised in high-income country populations. Nigerian placental physiology data addressing these pathways in pre-eclampsia-associated growth restriction are absent. Objectives: This study aims to characterise placental vascular architecture by three-dimensional power Doppler ultrasound indices, quantify trophoblast invasion depth by placental histomorphometry, and measure placental expression of hypoxia-inducible factor-1 alpha, vascular endothelial growth factor, placental growth factor, and matrix metalloproteinase-2 and -9 in women with pre-eclampsia and intrauterine growth restriction compared with normotensive controls at ESUT Teaching Hospital, Parklane, Enugu. Methods: Thirty pre-eclamptic women with intrauterine growth restriction, thirty pre-eclamptics without growth restriction, and thirty normotensive controls will be recruited at delivery. Placentae will be collected for histomorphometry and immunohistochemical protein quantification. Three-dimensional Doppler indices will be obtained antepartum. MANOVA with Bonferroni adjustment will compare group differences across molecular and vascular endpoints. Expected Outcomes: Pre-eclamptic growth-restricted placentae are hypothesised to exhibit shallowest trophoblast invasion, highest resistance vascular indices, and highest hypoxia-inducible factor-1 alpha with lowest vascular endothelial growth factor expression. Conclusion: This study will generate original placental physiology data fundamental to understanding perinatal outcomes in South East Nigeria. Keywords: pre-eclampsia, trophoblast invasion, intrauterine growth restriction, placental vascular physiology, Enugu.