Kidney disease and pregnancy: What you need to know

This is an automatically translated article.

The article was professionally consulted with Doctor Nguyen Thi Man - Obstetrician and Gynecologist - Department of Obstetrics and Gynecology - Vinmec Danang International General Hospital.
Approximately 2 to 3% of pregnant women develop kidney disease, 40 to 50% of which develop glomerulonephritis during pregnancy. It can be affirmed that kidney disease is one of the dangerous groups of diseases that directly affect the health of both mother and fetus.

1. The link between kidney disease and pregnancy

During pregnancy, a woman has profound changes in physiology and health, most notably in the urinary system. At this time, kidney diseases are easy to develop.
1.1. Changes in urinary tract and kidneys during pregnancy Two kidneys increase in volume, about 1 cm longer and about 4.5 grams heavier due to increased perfusion of renal parenchyma and interstitial tissue. The renal calyces, renal pelvis, and ureters are slightly dilated, especially in the right kidney. It has also been found that there is reflux of urine from the bladder to the ureter in pregnant women due to the compression of the fetus and hypotonicity due to the effect of some hormones such as progesterone. The main consequence of this dilation is urinary retention, which leads to urinary tract infections in pregnant women, such as glomerulonephritis during pregnancy, pyelonephritis, and lower urinary tract infections such as cystitis and urethritis. . It is necessary to thoroughly treat the infection with antibiotics that do not affect the fetus such as cephalexin, cifixim, zinat.

1.2. Renal hemodynamic changes during pregnancy Increases in glomerular filtration rate and renal perfusion, both of which increase by 40% during pregnancy, persist until birth. Early increases in perfusion due to increased cardiac output occur at 4 weeks of pregnancy, followed by an increase in extracellular and blood volume. This dilution of blood reduces albumin concentration and colloidal pressure, plasma osmolarity.
Abnormalities of the synthesis of hormones such as renin, prostaglandin... have vasoconstrictor effects or receptors of the renal cortex, which is believed to be the main cause of hemodynamic changes in the kidney. As a consequence, it causes a decrease in plasma creatinine, a decrease in plasma urea due to blood dilution and decreased tubular reabsorption, and a decrease in uric acid which has a prognostic value of decreased placental perfusion with the risk of fetal malnutrition and stillbirth. Increase the volume and fluid in the compartments, because during pregnancy, the mother's body weight increases by 12-15 kg. This increase in body weight is due to an increase of 6-8 liters of water, of which about 4-6 liters of water are in the extracellular space. The plasma volume doubles, which is a normal physiological phenomenon in pregnant women, so no intervention is required.

1.3. The effects of the fetus on kidney and urinary tract diseases During pregnancy, pregnant women can develop bacteriuria due to decreased tone and dilation of the urinary tract, accounting for 5-10%. Common types of bacteria E.Coli, Proteus, Klebsiella, Enterococus... Manifestations of bacteriuria: Acute pyelonephritis and cystitis urethra. Treatment: urine culture for antibiogram, treatment according to antibiotic chart.
Renal disease that causes hypertension with proteinuria and edema occurring from 20 weeks onwards is called preeclampsia. Decreased cardiac output and placental ischemia occur first causing the release of trophoblaste in the circulation causing intravascular coagulation. This phenomenon can occur in the glomerular capillaries which can cause acute renal failure.
Uterine ischemia is caused by the release of vasoconstrictors and possibly a lack of vasodilators leading to increased blood pressure. There is no physiological increase in renal blood flow and glomerular filtration rate so urea, creatinine and uric acid increase. Maternal complications cause eclampsia, placental abruption. In the fetus with fetal malnutrition, stillbirth, premature birth.
This is an obstetric emergency requiring medical treatment: Magnesium sulfate, hypotensive hydralazine, and sedation. At the same time, it is necessary to terminate the pregnancy, when medical treatment is not effective, in order to ensure the safety of the mother's life.

2. Common kidney diseases during pregnancy

2.1. Glomerulonephritis during pregnancy Symptoms of glomerulonephritis during pregnancy are very erratic, sometimes very discreet, so the mother does not know. Glomerulonephritis during pregnancy is detected only through tests. The functional changes of the lower urinary tract are important because inflammation often originates here. Therefore, when the symptoms of glomerulonephritis during pregnancy are still localized in the lower urinary tract, do not rush to conclude that the renal parenchyma is not related! Whenever a pregnant woman has a fever of unknown cause, immediate attention should be paid to glomerulonephritis during pregnancy.
If the fever is accompanied by chills, back pain and bladder inflammation, then the woman may have glomerulonephritis during pregnancy. At that time, it is possible that a Gram (-) bacteremia can lead to cardiovascular collapse and death; or an acute renal failure with severe sepsis accompanied by very serious cardiovascular collapse. Even more dangerous is that glomerulonephritis during pregnancy appears in a separate state of proteinuria without edema, no increase in blood pressure, which is difficult to diagnose. Or glomerulonephritis during pregnancy accompanied by gestational toxicity, hypertension and abnormally high protein-uria, the more severe the prognosis.
Glomerulonephritis during pregnancy will go away if it is treated early even if the infection is not very clear. Pregnant women need to have an ultrasound or X-ray to determine if it is a tumor, stone or stricture. These tests must also be repeated 6-8 weeks after birth, when the urinary tract has returned to normal.
The risk of premature birth, pregnancy failure, pyelonephritis - chronic kidney disease, high blood pressure... are unavoidable things.
Glomerulonephritis during pregnancy must be treated with antibiotics. But what antibiotic to use, for how long... must be prescribed by specialized doctors.
Note, not to catheterize pregnant women because it easily causes pyelonephritis - prolonged retrograde kidney, very difficult to treat.
2.2. Renal calyx dilatation in pregnant women

Dilated renal pelvis or dilated renal calyces is understood as the process of dilation due to water retention of the kidneys. The process of dilating the renal calyces for a long time will make the kidneys deformed. Specifically, the kidneys will enlarge and thin. The kidney is now shaped like a bag of water and is at risk of rupture at any time.
Dilatation of the renal pelvis in pregnant women occurs when the size of the kidneys increases during pregnancy: on ultrasound and radiographs, the length of the kidneys increases by about 1cm compared to pre-pregnancy. The size of the kidneys returns to normal after birth.
Pyelonephritis in pregnant women is often detected by ultrasound and pyelonephritis, which indicates fluid retention due to urinary obstruction. This fluid retention is usually mild, known as pyelonephritis in "physiological" pregnant women during pregnancy, and does not require treatment. However, these physiological changes are a risk factor for nephro- urinary tract infections in pregnant women.
Currently you find that the location of the kidney area is a bit sharp, most likely the reason is kidney - urology, you should see a doctor to be re-examined, do some more necessary tests to find the reason and treat. , avoid affecting the health of you and your unborn baby.
Since the cause of the pyelonephritis during pregnancy is due to the pregnancy process, the fact that treatment with drugs will only improve a little, it is imperative to wait until the condition is delivered. can be improved.
For women with kidney diseases such as glomerulonephritis during pregnancy, pyelonephritis in pregnant women will greatly affect the mother's health, so considering pregnancy, it is necessary to consult a doctor. obstetrician and consultant internist. During pregnancy must be under the care of an obstetrician and nephrologist.

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