Hydronephrosis In Pregnancy: What It Is, Causes & Treatment

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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 urinary tract obstruction or blockage.

You must consult your doctor immediately if you notice hydronephrosis 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 that 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.

Quick fact

Hydronephrosis during pregnancy becomes more prominent on the right side. However, the condition is not found in those whose ureters do not cross the pelvic brim (6).

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 or UTI during pregnancy. Therefore, it is estimated, around 90% of pregnant women may suffer from some form of hydronephrosis or urinary retention during pregnancy. An existence of hydronephrosis due to some pathological condition prenatally worsens the disorder (1).

Symptoms Of Hydronephrosis

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Symptoms vary based on the severity of the condition. Some women may have mild symptoms, while others may have none. Here are some typical symptoms of hydronephrosis during pregnancy.

• Acute flank pain or pain in the back and abdominal region
• Nausea and vomiting
• Constant urinary tract infection with painful urination
• Fever
• Colicky painⁱA sudden, intense, spasm-like stomach ache that can strike suddenly and is recurrent.
• Stains of blood in the urine or hematuria
• Chest pain
• Swelling of the legs
• Increased frequency of urination (2)

Causes Of Hydronephrosis

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The hormonal changes during pregnancy involving estrogen, progesterone, and prostaglandin-like agents cause disorders such as hydronephrosis and hydroureterⁱDilated ureters due to obstruction of urine flow resulting from the blockage of the ureter. (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 syndromeⁱAn unusual syndrome when a dilated ovarian vein leads to an obstruction of the ureters. , and functional causes, such as diabetes and vesicoureteral refluxⁱA disorder when the urine flows backward via one or both ureters and reaches the kidneys. , may also cause maternal hydronephrosis.

Quick fact

In some cases, hydronephrosis (due to blockage and swelling of the kidneys) occurs rapidly, while in others, it develops slowly (2).

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.

The graphical representation below illustrates the outcomes of a study conducted on 58 expectant mothers experiencing different levels of symptomatic ureterohydronephrosis. The results corroborate that maternal ureterohydronephrosis is a common anatomical modification during pregnancy. Also, its prevalence varies based on gestational age, with a higher frequency observed during the second and third trimesters.

Distribution of hydronephrosis cases according to gestational age

Diagnosis

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• 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.

• In rare cases, doctors may suggest advanced imaging techniques such as MRI or CT scans.

Risks

The obstetric complications and risks due to gestational hydronephrosis include preterm labor and delivery and pyelonephritisⁱA bacterial infection of the kidneys. . 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 suffering from a spontaneous renal rupture. If left untreated beyond a reasonable period, the kidney will permanently fail to function, leading to renal failure (3). However, regular monitoring and immediate treatment can help prevent long-term renal damage.

When To Seek Medical Assistance

An incidence of fever, acute pain in the abdomen, traces of blood in the urine, bladder dysfunction, or any other urological complications are all pointers to seek medical help immediately. 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.

1. Most cases with mild symptoms of gestational hydronephrosis with normal renal function can be treated symptomatically. Some of the treatments include anti-spasmodicsⁱA drug that reduces the contractions and spasms of abdominal muscles. , analgesics, proper hydration, left lateral position while sleeping, and treating urinary tract infection, if any.

2. 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.

3. 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). In severe cases leading to kidney failure, your obstetrician may suggest dialysis.

Dani Tippet, a first-time mother shares, “My second trimester was one I was looking forward to, as many women enjoy this part of pregnancy most. Unfortunately, I was greeted with excruciating pain caused by a kidney condition called hydronephrosis. I worked through this pain from my 25th week in pregnancy, up until my 33rd week. At that point, my urologist recommended I undergo surgery to relieve the pain and pressure I was experiencing for the safety and comfort of both myself and my baby (i).”

Prevention

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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).

Infographic: How To Keep Your Kidneys Healthy During Pregnancy?

Pregnancy induces changes in all aspects of kidney functions, including increased glomerular filtration rate and renal plasma flow. Regular prenatal checkups and controlling certain pregnancy complications are necessary to avoid kidney damage. Follow the tips given in the infographic below to promote kidney health during pregnancy.

Illustration: Momjunction Design Team

Are you unable to pass urine through your bladder during your pregnancy? You could be suffering from Hydronephrosis. Watch this video to know how specialists cater to you and your unborn child’s well-being.

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Reviewer Expert Author Editor Fact Checker

Dr. Arpita ChakrabortyMS

Dr. Arpita Chakraborty practices at Bombay Hospital, Mumbai and has eight years of experience in the field of ob/gyn. She has passed her medical training with distinction and bagged gold medals in various subjects. Dr. Chakraborty trained in advanced laparoscopy at Bombay Hospital and did FOGSI Certified Course in Obstetrics Ultrasonography.

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• 
  Dr. Himali Maniar PatelMBBS, DGO Dr. Himali M Patel is an Ahmedabad, India based gynecologist with 13 years of experience. She currently practices at Nisha Women's Hospital and IVF Centre. Dr. Patel did her graduation in Medicine at Bharati Vidyapeeth University, Pune and holds a diploma in Obstetrics and Gynecology.
  
  Dr. Himali M Patel is an Ahmedabad, India based gynecologist with 13 years of experience. She currently practices at Nisha Women's Hospital and IVF Centre. Dr. Patel did her graduation in Medicine at Bharati Vidyapeeth University, Pune and holds a diploma in Obstetrics and Gynecology.

shreeja pillaiMSc

Shreeja holds a postgraduate degree in Chemistry and diploma in Drug Regulatory Affairs from the University of Mumbai. Before joining MomJunction, she worked as a research analyst with a leading multinational pharmaceutical company.

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Rebecca MalachiBSc

Rebecca is a pregnancy writer and editor with a passion for delivering research-based and engaging content in areas of fertility, pregnancy, birth, and post-pregnancy. She did her graduation in Biotechnology and Genetics from Loyola Academy, Osmania University and obtained a certification in ‘Nutrition and Lifestyle in Pregnancy’ from Ludwig Maximilian University of Munich (LMU).

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Dr. Joyani DasM.Pharm, PhD

Dr. Joyani Das did her post-graduation from Birla Institute of Technology, Mesra and PhD in Pharmacology. Previously, she worked as an associate professor, faculty of Pharmacology, for two years. With her research background in preclinical studies and a zeal for scientific writing, she joined MomJunction as a health writer.

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