The primary defect responsible for defective placentation in early-onset pre-eclampsia is best described as:
- A Failure of endovascular trophoblast invasion resulting in non-remodelling of spiral arteries ✓
- B Excessive invasion of spiral arteries by cytotrophoblast leading to arteriovenous shunts
- C Thrombosis of uterine veins causing placental hypoperfusion
- D Abnormal fetal karyotype impairing placental angiogenesis
Correct answer: A. Failure of endovascular trophoblast invasion resulting in non-remodelling of spiral arteries
Explanation
In normal placentation, extravillous cytotrophoblast invades the spiral arteries and replaces their muscular and elastic layers, converting them into low-resistance vessels. In early-onset pre-eclampsia this second wave of invasion fails, leaving narrow, musculatised, high-resistance spiral arteries prone to vasospasm and ischemia. Excess invasion describes accreta spectrum pathology, venous thrombosis is not the accepted mechanism, and aneuploidy is not the classic defect, though it is a risk modifier.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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