Renal Disease in Pregnancy 2019 th Edition Ebook
Renal Disease in Pregnancy 2019 th Edition Ebook Remarkable and unique changes enable the kidneys to adjust to the increased metabolic demands of pregnancy. Renal adaption occurs following conception, is maximal prior to major increases in uteroplacental blood flow and is maintained until at least late gestation. Adjustment of systemic and renal homeostasis enables enhanced glomerular filtration, volume expansion, modified electrolyte and acid base balance and augmented erythropoietin and active vitamin D synthesis. These alterations are likely to contribute to successful pregnancy outcomes. Current understandings of underlying mechanisms of gestational transformations are outlined in what follows, and potential pathophysiological pathways of pregnancyassociated deterioration in renal function are discussed.
Increases in renal blood flow and interstitial space , equating to approximately 1 cm in length . Dilatation of the renal tract (calyces, renal pelvis and ureter) is evident in 90 percent of women by the third trimester , and is more prominent on the right. This effect is proposed to be the consequence of the ureter passing over the right iliac artery.
However, renal tract dilatation is also recognized in transplanted kidneys, implying that circulating factors are contributory. Urological complications are discussed in more detail in Chapter 15. Renal Function in Pregnancy Renal Blood Flow Ovulation is followed by an increase in renal plasma flow, as measured by para-aminohippurate clearance.
After conception, there are further increases in
02effective renal plasma flow, reaching rates 50–85 percent greater than nonpregnant values .
Longitudinal assessments of effective renal plasma flow in healthy women during pregnancy and postpartum consistently report augmented flow. There is discrepancy at later gestation, however, with some reports of up to 20 percent reduced flow toward term [3, 4], and others of sustained blood flow . Positional changes in late pregnancy may influence renal hemodynamics , but this is not confirmed by all studies .