Hydronephrosis means dilation or swelling of the part of the kidney that collects urine, usually because urine is not draining normally.

During pregnancy, some degree of dilation of the urinary collecting system can occur because of normal anatomical and hormonal changes. This is sometimes called physiological hydronephrosis of pregnancy.

However, hydronephrosis can also occur because something is obstructing urine flow, such as a kidney stone, ureteral narrowing, blood clot or another urinary-tract problem.

Therefore, finding hydronephrosis during pregnancy does not automatically mean that there is a dangerous kidney condition.

The important question is whether the dilation is a normal pregnancy-related change or whether there is clinically significant obstruction requiring treatment.

At Prabhakar Bhurke Clinic, Dr. Sandip Prabhakar Bhurke, super specialist nephrologist and transplant physician, provides individualized kidney evaluation for pregnant patients with abnormal kidney-function tests, urinary symptoms and suspected urinary obstruction.

Why Can Pregnancy Cause Hydronephrosis?

Pregnancy produces several changes in the urinary system.

As the uterus enlarges, it can put pressure on portions of the ureters. Hormonal changes can also reduce ureteral muscle tone and slow the movement of urine.

As a result, urine may move more slowly from the kidneys toward the bladder, producing dilation of the renal pelvis and ureters.

Pregnancy-related hydronephrosis is often more pronounced on the right side, although either kidney can be affected.

This physiological dilation is different from hydronephrosis caused by a physical blockage.

Is Hydronephrosis in Pregnancy Always Dangerous?

No.

Mild or moderate urinary-tract dilation can occur as part of normal pregnancy-related changes and may not require a procedure.

However, further assessment becomes important when hydronephrosis is associated with:

• Significant or persistent pain

• Fever or chills

• Blood in urine

• Recurrent urinary infection

• Reduced urine output

• Kidney stones

• Rising creatinine

• Severe urinary obstruction

• Worsening symptoms

The severity and cause need to be assessed rather than judging the condition only from the ultrasound finding.

Common Causes of Hydronephrosis in Pregnancy

Physiological Changes of Pregnancy

Normal hormonal and anatomical changes can slow urine drainage and produce urinary-system dilation.

This is a common explanation when the pregnant patient has no evidence of significant obstruction or kidney dysfunction.

Kidney Stones

Pregnancy does not prevent kidney stones.

A stone can become lodged in the ureter and interfere with urine flow, potentially producing hydronephrosis and renal colic.

Symptoms may include severe flank pain, nausea, vomiting or blood in the urine.

Ureteral Obstruction

Less commonly, urine flow can be impaired by:

• Ureteral narrowing

• Blood clots

• Structural abnormalities

• Masses

• Other urinary-tract conditions

The exact cause requires appropriate clinical and imaging assessment.

Urinary Infection With Obstruction

An infection occurring behind an obstruction can become serious.

A pregnant patient with fever, chills, flank pain and suspected urinary obstruction needs prompt medical evaluation.

What Symptoms Can Hydronephrosis Cause During Pregnancy?

Hydronephrosis itself may produce no symptoms.

When symptoms occur, they can include:

• Flank or side pain

• Back discomfort

• Lower abdominal pain

• Pain associated with urination

• Nausea

• Vomiting

• Blood in urine

• Increased urinary frequency

• Fever or chills when infection is present

These symptoms are not specific to hydronephrosis, and pregnancy itself can cause several urinary and abdominal symptoms.

Medical assessment is therefore important when symptoms are persistent, severe or unusual.

Hydronephrosis and Kidney Stone During Pregnancy

A kidney stone that blocks the ureter can cause urine to build up behind the obstruction.

This may result in hydronephrosis.

Management of kidney stones during pregnancy requires special consideration because the health of both the mother and fetus must be taken into account.

If symptoms are mild and there is no infection, severe obstruction or kidney-function deterioration, conservative management may sometimes be appropriate.

If obstruction becomes significant or complications develop, intervention may be necessary.

How Is Hydronephrosis Diagnosed During Pregnancy?

Ultrasound

Ultrasound is usually an important first-line imaging method during pregnancy because it does not use ionizing radiation.

It can provide information about:

• Kidney dilation

• Possible urinary obstruction

• Kidney stones in some cases

• Bladder abnormalities

• Changes over time

However, ultrasound may not always identify the exact cause of obstruction.

Urine Testing

A urine test may be used to look for:

• Blood

• White blood cells

• Bacteria

• Protein

• Other abnormalities

A urine culture may be required when infection is suspected.

Blood Tests

Depending on the situation, the doctor may evaluate:

• Serum creatinine

• Electrolytes

• Blood count

• Other relevant tests

A rising creatinine can indicate worsening kidney function and may change the urgency of treatment.

Additional Imaging

When ultrasound does not provide enough information, further imaging may occasionally be considered by the treating team after weighing the potential benefits and risks during pregnancy.

The choice depends on gestational age, symptoms, suspected cause and clinical urgency.

Hydronephrosis in Pregnancy Treatment: What Are the Options?

Treatment is based on the cause, severity, symptoms, kidney function and presence or absence of infection.

Observation and Monitoring

If hydronephrosis appears consistent with normal pregnancy-related dilation and the mother has no significant obstruction or complications, monitoring may be all that is required.

Follow-up may include:

• Repeat ultrasound

• Kidney-function testing when appropriate

• Urine testing

• Monitoring of pain and urinary symptoms

Pain Management

If discomfort is present, the treating doctor can recommend a pain-relief option that is appropriate for pregnancy.

Pregnant patients should not self-medicate with painkillers, particularly because the safety of medications can vary according to the stage of pregnancy and individual health.

Treatment of Urinary Infection

If a bacterial urinary infection is identified, the treating doctor may prescribe an antibiotic considered appropriate during pregnancy.

The antibiotic should be selected according to the infection, culture results when available, allergies, kidney function and pregnancy considerations.

Treating a Kidney Stone

If a stone is responsible for obstruction, management depends on its size, location, symptoms and the degree of obstruction.

Some stones can be observed under medical supervision.

Others may require a procedure when there is:

• Persistent severe pain

• Significant obstruction

• Infection

• Worsening kidney function

• Failure of conservative management

Ureteral Stent

A ureteral stent may be used to bypass an obstruction and allow urine to drain from the kidney into the bladder.

A stent can be particularly useful when obstruction needs to be relieved during pregnancy and definitive stone treatment needs to be postponed.

Stents may cause urinary frequency, discomfort or blood in the urine and usually require planned follow-up.

Nephrostomy

In selected cases, a percutaneous nephrostomy may be used to drain urine directly from the kidney through a tube placed through the skin.

This may be considered when urgent drainage is necessary or when a ureteral stent is unsuitable or unsuccessful.

The decision is made by the treating specialist team.

Is Surgery for Hydronephrosis Safe During Pregnancy?

A procedure is not automatically required simply because hydronephrosis is seen on ultrasound.

When intervention is necessary, the timing and type of procedure are carefully selected.

For example, if a blocked and infected urinary tract requires urgent drainage, delaying treatment can be more dangerous than performing an appropriate drainage procedure.

Definitive treatment of a stone may sometimes be postponed until after delivery when clinically safe, while temporary drainage maintains urine flow.

In other circumstances, ureteroscopy may be considered during pregnancy by an experienced specialist team.

The decision should be individualized according to the mother's condition, gestational age, obstruction and available expertise.

Can Hydronephrosis Affect the Baby?

Hydronephrosis itself does not automatically mean that the baby will be harmed.

The concern is primarily related to the underlying cause and severity of the mother's illness.

For example, severe infection, significant obstruction, dehydration or serious maternal illness can require prompt treatment during pregnancy.

Pregnant patients with kidney-related symptoms should therefore receive coordinated care involving the appropriate obstetric and kidney or urinary specialists.

Does Hydronephrosis Go Away After Pregnancy?

When hydronephrosis is primarily related to pregnancy-induced anatomical and hormonal changes, urinary-tract dilation often improves after delivery as these changes resolve.

Hydronephrosis caused by a kidney stone, structural narrowing or another persistent obstruction may not resolve simply because pregnancy ends.

Follow-up may therefore be necessary when a structural cause is suspected.

What Happens If Hydronephrosis Is Left Untreated?

The consequences depend on the underlying cause.

Mild physiological dilation may not cause permanent kidney damage.

In contrast, prolonged significant obstruction can impair kidney function.

An obstructed urinary tract can also increase concern when infection develops at the same time.

Possible complications of significant untreated obstruction include:

• Worsening hydronephrosis

• Recurrent infection

• Reduced kidney function

• Severe pain

• Urinary drainage problems

Prompt assessment is especially important when creatinine rises or urine output decreases.

When Is Hydronephrosis During Pregnancy an Emergency?

A pregnant patient should seek urgent medical attention for symptoms such as:

• Fever or chills

• Severe flank or abdominal pain

• Persistent vomiting

• Very little or no urine

• Blood in urine with worsening symptoms

• Severe weakness or fainting

• Confusion

• Rapid deterioration in general health

Fever combined with urinary obstruction can indicate an infected obstructed urinary tract and requires urgent treatment.

What Should You Avoid If You Have Hydronephrosis During Pregnancy?

Do not attempt to treat hydronephrosis independently with home remedies.

Avoid:

• Taking unprescribed painkillers

• Using herbal kidney-cleansing products

• Taking antibiotics without medical advice

• Delaying evaluation of fever or severe pain

• Drinking excessive amounts of water to “flush” an obstruction

Fluid intake should remain appropriate for pregnancy and the individual's medical condition.

If a urinary obstruction is present, excessive water intake cannot physically remove the blockage.

Hydronephrosis in Pregnancy and Kidney Function

Most pregnancy-related hydronephrosis does not automatically mean that kidney function is impaired.

However, significant obstruction or infection can affect kidney function.

Doctors may therefore monitor:

• Creatinine

• eGFR or other measures of kidney function as clinically appropriate

• Urine output

• Electrolytes

• Urinalysis

• Blood pressure

Pregnancy changes the normal interpretation of some kidney-related measurements, so results should be interpreted by a clinician familiar with pregnancy.

Who Should Manage Hydronephrosis During Pregnancy?

Management may involve more than one specialist.

Depending on the cause, care may include:

• Obstetrician

• Nephrologist

• Urologist

• Radiologist

• Other specialists when required

A nephrologist can assess kidney function and medical kidney conditions, while a urologist may be involved when a urinary obstruction or stone requires a procedure.

The obstetric team remains important for monitoring the pregnancy.

Hydronephrosis in Pregnancy Evaluation at Prabhakar Bhurke Clinic

At Prabhakar Bhurke Clinic, Dr. Sandip Prabhakar Bhurke, super specialist nephrologist and transplant physician, provides individualized kidney evaluation for pregnant patients with suspected kidney-function abnormalities, urinary obstruction or related kidney conditions.

Assessment may include:

• Review of pregnancy and medical history

• Kidney-function evaluation

• Creatinine and laboratory assessment

• Urine testing

• Review of ultrasound findings

• Assessment for kidney stones

• Evaluation of urinary obstruction

• Blood-pressure monitoring

• Infection assessment

• Coordination with obstetric and urological specialists when required

Treatment decisions are individualized according to the pregnancy stage, kidney function, symptoms and underlying diagnosis.

Frequently Asked Questions

Is hydronephrosis common during pregnancy?

Dilation of the urinary collecting system can occur during pregnancy because of hormonal and anatomical changes. Not every case represents pathological obstruction.

Is hydronephrosis during pregnancy dangerous?

Not necessarily. Mild physiological hydronephrosis may not require intervention. Significant obstruction, infection, severe pain or impaired kidney function requires medical assessment.

Can a kidney stone cause hydronephrosis during pregnancy?

Yes. A stone lodged in the ureter can obstruct urine flow and cause hydronephrosis.

What is the safest treatment for hydronephrosis in pregnancy?

There is no single treatment that is safest for every patient. Observation, medical treatment, temporary drainage with a ureteral stent or nephrostomy, and selected stone procedures may be considered depending on the cause and severity.

Can I drink more water to treat hydronephrosis?

No. Excessive water cannot remove a physical urinary obstruction and may be inappropriate in some clinical situations. Fluid intake should follow medical advice.

Can hydronephrosis damage the kidney during pregnancy?

Significant or prolonged obstruction can impair kidney function. Pregnancy-related physiological dilation without obstruction generally has a different prognosis.

When should a pregnant woman with hydronephrosis see a doctor urgently?

Fever, chills, severe flank pain, persistent vomiting, very low urine output, severe weakness or rapidly worsening symptoms require urgent medical evaluation.

Conclusion

Hydronephrosis in pregnancy treatment depends on whether the kidney dilation is a normal consequence of pregnancy or the result of an actual urinary obstruction.

Pregnancy-related dilation may simply require monitoring, while kidney stones, infection or significant obstruction may require active treatment. Ultrasound, urine testing and kidney-function assessment can help doctors determine the likely cause.

When intervention becomes necessary, treatment is selected carefully to protect the health of both mother and baby. Depending on the circumstances, management may include observation, pregnancy-appropriate medicines, treatment of infection, ureteral stenting, nephrostomy or selected stone procedures.

Pregnant patients should not attempt to treat hydronephrosis with excessive water, unprescribed medicines or herbal remedies.

For individualized assessment of hydronephrosis, kidney-function concerns and urinary problems during pregnancy, consult Dr. Sandip Prabhakar Bhurke at Prabhakar Bhurke Clinic.

Medical Disclaimer

This article is intended for general educational and informational purposes only and should not be considered medical diagnosis, treatment or individualized medical advice. Hydronephrosis during pregnancy can have different causes, ranging from normal pregnancy-related urinary-tract dilation to kidney stones, infection or significant obstruction. Treatment must be individualized according to gestational age, symptoms, kidney function, imaging findings and maternal and fetal considerations. Pregnant patients should not take painkillers, antibiotics, herbal products or other medicines without advice from their healthcare professional. Do not attempt to treat a urinary obstruction by excessive fluid intake. Fever or chills with suspected urinary obstruction, severe pain, persistent vomiting, very low or absent urine output, confusion or rapid deterioration requires urgent medical assessment. Consult Dr. Sandip Prabhakar Bhurke, an obstetrician, urologist or another qualified healthcare professional as appropriate for personalized care.