Enfermedades Renales y Embarazo

Management of Renal D i s e a s e in Preg n a n c y
Tiina Podymow, MDa, Phyllis August, Ayub Akbari, MDc,*
KEYWORDS  Pregnancy  Renal disease  Glomerulonephritis  Dialysis  Renal function
b MD, MPH ,

In patients with renal disease who become pregnant, the possible harmful effects of pregnancy on kidney function and the impact of renal disease on pregnancy outcome should be considered.In this context, the nephrologist’s role is to assess the risk for worsening renal function in pregnancy; ideally nephrologic opinion should be sought before conception. Assessment of maternal hypertension is also crucial, because it contributes significantly to the risk for deteriorating renal function and increases the risk for preeclampsia, preterm delivery, intrauterine growth restriction, andperinatal mortality. Management of pregnant women with kidney disease may be complicated, and requires an understanding of the physiologic changes associated with pregnancy and close teamwork between obstetricians and nephrologists. Although some areas in obstetric medicine have been extensively studied in randomized controlled trials (eg, prevention of preeclampsia), renal disease in pregnancyhas been so less commonly, and the quality of the evidence guiding clinical practice has not been of the highest level. Most evidence consists of case series with modest numbers of subjects. Based on population studies, the prevalence of chronic kidney disease in women of childbearing age is 0.03% to 0.2% of all pregnancies.
RENAL ANATOMY AND PHYSIOLOGY IN PREGNANCY Anatomic and Functional Changesin Urinary Tract

Normally in pregnancy, increased renal blood flow and glomerular hypertrophy result in an increase in kidney length of approximately 1 cm during normal gestation, and overall kidney volume increases by up to 30%.1 The major anatomic alterations of the urinary

Division of Nephrology, McGill University, 687 Pine Avenue West Ross 2.38, Montreal, QC H3A 1A1, Canada b Divisionof Nephrology and Hypertension, Weill Medical College of Cornell University, 525 East 68th Street, Starr 437, NY 10021, USA c Division of Nephrology, University of Ottawa, Kidney Research Center, 1967 Riverside Drive, Ottawa, ON, K1H 7W9, Canada * Corresponding author. E-mail address: aakbari@ottawahospital.on.ca Obstet Gynecol Clin N Am 37 (2010) 195–210 doi:10.1016/j.ogc.2010.02.012obgyn.theclinics.com 0889-8545/10/$ – see front matter ª 2010 Elsevier Inc. All rights reserved.

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tract during pregnancy are seen in the collecting system, where calyces, renal pelvises, and ureters dilate, often giving the erroneous impression of obstructive uropathy.2 The cause of the ureteral dilation has been attributed to hormonal mechanisms, such as increased progesterone,and mechanical obstruction by the enlarging uterus. These morphologic changes result in stasis in the urinary tract and a higher risk among pregnant women with asymptomatic bacteriuria for progression to pyelonephritis, particularly in those who have a history of prior urinary tract infections.3 Rarely, ‘‘overdistension syndrome’’ may occur, which is a pregnancy-related syndrome characterized bysevere hydronephrosis, abdominal pain, decline in renal function, and even hypertension, which may respond to lateral recumbency or require stent placement.
Renal Hemodynamics in Pregnancy

Marked vasodilation is a hallmark of pregnancy and occurs by 6 weeks gestation. Vasodilation is accompanied by a decrease in blood pressure, increase in cardiac output, and increases in renal plasma flow andglomerular filtration, all of which persist until late gestation. Increased progesterone, estrogen, nitric oxide, and relaxin have all been implicated as vasodilatory mediators. Because renal plasma flow increases slightly more than the glomerular filtration rate (GFR), filtration fraction remains constant or slightly lower in pregnancy. Increases in renal hemodynamics reach a maximum during...