Renal Function and the Role of the Renin-Angiotensin-Aldosterone System (RAAS) in Normal Pregnancy and Pre-Eclampsia.

Pre-eclampsia (PE) is a complex, advancing condition marked either by the recent emergence of hypertension and proteinuria or by the recent onset of hypertension accompanied by notable end-organ impairment, which may occur with or without proteinuria. PE usually appears in the postpartum phase or after the 20th week of gestation, though it might appear sooner in cases of molar pregnancy. This disorder is a serious multisystem condition during pregnancy that can lead to serious, life-threatening complications for both the mother and the fetus if it is not diagnosed and managed promptly. These changes result from widespread and intense vasoconstriction caused by renin, angiotensin II (Ang II), aldosterone, and catecholamines. The renin-angiotensin-aldosterone system (RAAS) and its sequence of signaling reactions demonstrate its crucial role in regulating blood pressure and electrolyte balance that diverges in PE from that observed in healthy pregnancies. However, it is widely recognized that the above description is incomplete for pre-eclampsia and further relationships should be analyzed. The purpose of this article is to review and synthesize alterations in renal function and the RAAS during normal pregnancy and pre-eclampsia. We aim to provide clinical gynecologists with a comprehensive understanding of how pregnancy-specific adaptations can impact renal function and the RAAS, as well as the deviations observed in pre-eclampsia. This information is essential to enhance clinical awareness, improve the accuracy of diagnosis, and support evidence-based decision-making in the management of pregnant patients, especially those complicated by pre-eclampsia.