Hydronephrosis refers to the swelling of the kidney due to the accumulation of urine, and the condition is known to affect 90% of pregnant women (1). In this condition, the kidney swells up as the urine is unable to pass through it and reach the bladder due to an obstruction or blockage. You must consult your doctor immediately if you notice the symptoms to prevent further complications. Read on to know more about hydronephrosis, including its causes, signs and symptoms, treatment, and prevention options.
What Is Hydronephrosis?
Hydronephrosis in pregnancy is not a disease per say. 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 as a normal physiological 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/gestational hydronephrosis. The asymptomatic dilation of the renal calyces, the renal pelvis and the upper two-thirds of ureters, during pregnancy results in this typical condition. Also referred to as gestational hydronephrosis, it is also associated 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. An existence of hydronephrosis due to some pathological condition prenatally worsens the disorder (1).
Symptoms Of Hydronephrosis
Here are a few symptoms of hydronephrosis during pregnancy. 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 (2)
Causes Of Hydronephrosis
The hormonal changes during pregnancy involving estrogen, progesterone, and prostaglandin-like agents cause disorders such as hydronephrosis and hydroureter (Ureteral Ectasia). Pregnancy causes 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 pressure over the ureters (pipes that connect the kidney to the urinary bladder), leading to the dilatation of the ureters and hence contributing to the incidence of hydroureteronephrosis. Increasing gestational age and growth of the uterus outside the pelvis can decrease this pressure on the ureters (3). Similarly, the pregnancy-related hormonal effect can also cause fetal hydronephrosis up to a limited extent. There could be other causes of maternal hydronephrosis too. Kidney stones, blood clots, stricture or scarring of the kidneys, bladder cancer, urethral stricture, etc., are some of the intrinsic causes of maternal hydronephrosis. Similarly, external causes, such as cervical cancer and ovarian vein syndrome, and functional causes, such as diabetes and vesicoureteral reflux, may also cause maternal hydronephrosis.
Facts
The gestational hydronephrosis usually occurs in the second trimester. It affects almost 90% of pregnancies by 26 to 28 weeks of gestation.
The incidence of ureteral and kidney dilatation is greater in nulliparous patients. (A woman who has not carried the pregnancy beyond 20 weeks is termed nulliparous).
Mostly gestational hydronephrosis disappears on its own, without any form of treatment. The ideal period is six weeks after delivery, but sometimes, it may persist longer.
Diagnosis
Ultrasound scan can help in differentiating physiological hydronephrosis from obstruction secondary to renal stones/calculus.
Analysis of urine to determine an infection.
Blood test to check for anemia.
Renal function test to detect the proper functioning of kidneys.
Risks
The complications and risks due to gestational hydronephrosis include preterm labor and delivery and pyelonephritis. A very rare but potentially life-threatening complication associated with severe 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. If left untreated beyond a reasonable period, the kidney will permanently fail to function (3).
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 slight symptoms, even in the case of a single kidney, should be brought to the attention of your doctor immediately.
Hydronephrosis In Pregnancy Treatment
The treatment of symptomatic gestational hydronephrosis during pregnancy is carefully performed through different stages. Take a look at them.
- Most cases with mild symptoms of gestational hydronephrosis with normal renal function can be treated symptomatically. Some of the treatments include anti-spasmodics, analgesics, proper hydration, left lateral position while sleeping, and treating urinary tract infection, if any.
- Draining the urine through a thin catheter inserted into the bladder or directly to the kidney through the skin under local anesthesia relieves the pressure on the kidneys.
- Treating the underlying cause, which primarily caused the blockage, is the next line of management. A surgery called ureteral stenting usually removes the obstruction. Different causes will have different treatments. For instance, if a large kidney stone triggers hydronephrosis, sound waves or lasers are used to break it (4).
Prevention
Kidney diseases often have no/mild 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 disease. A regular urine test and blood test can help us in finding the prevalence of any kidney disorders in pregnancy (5).
