Hydronephrosis During Pregnancy - Causes, Symptoms & Treatments

Hydronephrosis During Pregnancy

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Did you know that around 90% of pregnant women suffer from hydronephrosis in one form or the other? This might sound shocking to you, but that is the result of a number of reports from recent times. If you are an expecting mother, it is high time you developed an awareness of Hydronephrosis to stay safe during your pregnancy.

What Is Hydronephrosis?

Hydronephrosis is not a disease. It is a structural condition which typically occurs in one kidney or when chronic, affects both the kidneys. The failure of normal drainage of urine from the kidney to the urinary bladder can result in the swelling of either one of the kidneys or both. This condition commonly refers to Hydronephrosis. It may happen due to a normal variant or an underlying illness.

When the swelling affects one of the kidneys, it is called Unilateral Hydronephrosis. While, when both the kidneys are simultaneously affected, the disorder is called Bilateral Hydronephrosis.

Maternal Hydronephrosis:

A condition of developing Hydronephrosis during pregnancy, due to the presence of the fetus within the womb, is Maternal Hydronephrosis. The asymptomatic dilation of the renal calyces, the renal pelvis and the upper two-thirds of uterus during pregnancy results in this typical condition.(1)

Also referred to as gestational hydronephrosis, it associates with the common trouble of urinary tract infection in pregnant women. Therefore, it is estimated, around 90% of pregnant women suffer from some form of Hydronephrosis during pregnancy. The dilation is often more prominent on the right side of the body (85%) than the left side (15%). The ureteral dilation does not occur below the pelvic brim. An existence of Hydronephrosis due to some pathological condition prenatally worsens the disorder. (2)

[ Read: Kidney Infection During Pregnancy ]


Here are a few of hydronephrosis during pregnancy symptoms. However, in some cases, there will be no symptoms at all. Symptoms depend on whether the swelling occurs acutely, progressively or more gradually.

  • Acute flank pain or pain in the back and abdominal region
  • Nausea and vomiting
  • Constant urinary tract infection with painful urination
  • Fever
  • Colicky pain
  • Stains of blood in the urine
  • Chest pain
  • Swelling of the legs
  • Increased frequency of urination (3)

Causes Of Hydronephrosis:

The hormonal changes during pregnancy involving estrogen, progesterone, and prostaglandin like agents cause disorders like Hydronephrosis and Ureter Ectasis.

Pregnancy results in generalized relaxation of smooth muscles due to the effect of progesterone. Along with dextro-rotation of the uterus, the incidence of hydronephrosis in pregnant women becomes greater.The growing weight of the uterus in a limited pelvic space can cause dilation of the uterus and hence contribute to the incidence of Hydronephrosis. Increasing gestational age and growth of the uterus outside the pelvis can decrease this pressure on the ureters.Increased hydration can result in an increased degree of Hydronephrosis.

Pregnancy increases the renal blood flow to up to 75% and approximate 50% increase in the Glomerular Filtration Rate (GFR). The GFR is a test used to check how well the kidneys are working. Therefore, the incidence of fetal Hydronephrosis in pregnancy increases. (4)

The obstruction or the blockage in the urinary tract can occur congenitally in a fetus or may be one of the physiological responses to pregnancy. Kidney stones, blood clots or a stricture or scarring of the kidneys, bladder cancer, urethral stricture, etc. are few of the intrinsic causes of Hydronephrosis. Similarly, external causes of Cervical Cancer, the Ovarian Vein Syndrome and functional causes like Diabetes and Vesicoureteral Reflux can also result in Hydronephrosis.


  • The gestational Hydronephrosis usually occurs in the second trimester. It affects almost 90% of pregnancies by the 26th and 28th weeks.
  • The incidence of dilation is greater in nulliparous patients. A woman who has not carried the pregnancy beyond 20 weeks is termed nulliparous.
  • Mostly Hydronephrosis disappears on its own, without any form of treatment. The ideal period is six weeks after delivery, but sometimes, it may persist longer.


  • Ultrasound scan can help in differentiating physiologic Hydronephrosis from obstruction secondary to calculus disease.
  • Analysis of urine to determine an infection.
  • Blood test to check for anemia.
  • Electrolyte analysis and the GFR to detect the proper functioning of kidneys. (5)


A rare but potentially life-threatening complication associated with Gestational Hydronephrosis is a spontaneous renal rupture. It occurs due to increased hydrostatic pressure within the collecting structures that exceeds the holding capacity of the calyceal-renal capsular junctions.

Kidneys with prior damage before pregnancy are more susceptible to suffer from a spontaneous renal rupture.(6)

If left untreated beyond a reasonable period, the kidney will permanently fail to function.

When To Seek Medical Assistance:

An incidence of fever, acute pain in the abdomen or traces of blood in the urine are all pointers to immediately seek medical help. Hydronephrosis can be fatal in pregnant women with just one kidney. Therefore, even the development of light symptoms should be brought to the attention of your doctor.

Hydronephrosis In Pregnancy Treatment:

The treatment of Hydronephrosis during pregnancy is carefully performed through different stages. Take a look at them.

1. Draining the urine through a thin catheter inserted into the bladder or directly to the kidney through the skin. It relieves the pressure of the urine in the kidneys.

2. Treating the underlying cause which primarily caused the blockage is the next step in line. A surgery called Ureteral Stenting usually removes the obstruction. Different causes will have different treatments. For instance, if it is a kidney stone that triggered Hydronephrosis, sound waves or lasers are used to break it.

3. But if it is purely pregnancy that caused the disorder, nothing much can be done to treat the disorder. You just have to wait till it completes its natural course to heal. However, the process of draining the excess urine through a catheter will be done to reduce the pressure on the kidneys and preventing chances of further damage.(7)


Kidney diseases often have no symptoms. Hence, it can go undetected if not tested at the right time. Early detection and treatment can slow or prevent the progression of kidney’s disease. A regular urine test and blood test can help in finding the prevalence of any kidney disorders in pregnancy. (8)

Regularly consult your practitioner throughout pregnancy and make sure you don’t show any warning signs of renal disorders. Do you doubt whether you have a kidney disorder? Raise your queries to us.

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