Hypertension during pregnancy remains a leading cause of maternal and fetal morbidity and mortality. The frequency (5 to 10% of pregnancies) and potential severity of these diseases, both for the mother and the child, are reasons for standardizing and optimizing medical practices. The cause of hypertension during pregnancy is quite complex, as it depends on a number of factors. Among the hypertensive disorders in pregnancy (HDP), the pathophysiology of pre-eclampsia (one of the most studied in terms of severity) remains poorly understood. The evolution of international guidelines in recent years has made it possible to distinguish various HDP, but schematically we distinguish two main entities by the existence of proteinuria from and after the 20th week of amenorrhea and by maternal-fetal complications, more serious in pre-eclampsia than in gestational hypertension. Acute placental vasculature and blood flow abnormalities were observed during gestational hypertension and preeclampsia, and maybe due to generalized vascular endothelial activation and vasospasm resulting in systemic hypertension and organ hypoperfusion. Endothelial dysfunction (ED) and abnormal expression of several specific blood biomarkers are now well accepted as characteristics of preeclampsia as a leader. However, the progression of any HDP to preeclampsia is possible, but difficult to predict. By way of example, among between 15 and 40 % of gestational hypertension cases progress to preeclampsia, suggesting that it is the same worsening disease. ED could be pre-existing (chronic, white-coat or masked hypertension) but also at the origin of gestational hypertension (unclassified hypertension, transient pregnancy hypertension), and subsequent development of preeclampsia through an imbalance between pro- and anti-angiogenic factors. An imbalance of pro-angiogenic and anti-angiogenic proteins can testify to ED, as can adequate levels of endothelial microparticles. The main objective of this research is to assess the presence of urinary endothelial microparticles in stable pregnant women with hypertensive disorder of pregnancy as a marker for the occurrence of pre-eclampsia during pregnancy.