What effect does pre-eclampsia have on the spiral arteries?

In pre-eclampsia, the spiral arteries undergo significant pathological changes that result in constriction. Normally, during a healthy pregnancy, trophoblastic cells from the placenta invade these arteries and induce remodeling that leads to a decrease in resistance and increased blood flow to ensure adequate perfusion to the placenta. However, in pre-eclampsia, this remodeling is impaired due to inadequate trophoblastic invasion, leading to persistent constriction of the spiral arteries.

The constriction of these arteries is a critical factor in the development of placental insufficiency and the subsequent clinical manifestations of pre-eclampsia. The result of the constricted spiral arteries is inadequate blood supply to the placenta, which can lead to fetal growth restriction, placental abruption, and other complications. Understanding this mechanism is essential for managing and monitoring pregnancies affected by pre-eclampsia.