What is the earliest and most reliable clinical manifestation of pre-eclampsia?

The earliest and most reliable clinical manifestation of pre-eclampsia is the elevation of blood pressure. Pre-eclampsia is characterized by new-onset hypertension and often occurs after 20 weeks of gestation. Elevated blood pressure serves as a crucial indicator for the development of the condition, as it reflects the underlying pathophysiological changes associated with pre-eclampsia, such as the vascular dysfunction and increased peripheral resistance.

While other symptoms may develop as the condition progresses, such as proteinuria, excessive weight gain, edema, headache, and visual disturbances, these manifestations can also be seen in normal pregnancies or other conditions. Therefore, they are not considered as early or as reliable in diagnosing pre-eclampsia as the acute rise in blood pressure. Early detection of elevated blood pressure allows for timely management and monitoring to prevent complications for both the mother and the fetus.