Hydronephrosis (HN) during pregnancy is a medical condition characterized by the swelling or enlargement of one or both kidneys due to the accumulation of urine. This condition occurs when there is an obstruction in the urinary tract, preventing the normal flow of urine from the kidneys to the bladder. Pregnancy-related changes, such as hormonal fluctuations and the pressure exerted by the growing uterus, can contribute to the development of hydronephrosis in expectant mothers.

The most common cause of hydronephrosis during pregnancy is the compression of the ureters, the tubes that carry urine from the kidneys to the bladder, by the expanding uterus. This compression can lead to a backup of urine, causing the kidneys to swell.

Symptoms of hydronephrosis during pregnancy may include pain or discomfort in the lower abdomen or back, frequent urination, and urinary tract infections. In some cases, hydronephrosis can be asymptomatic and only detected through routine prenatal screenings.

Management of hydronephrosis during pregnancy may involve monitoring the condition closely, alleviating symptoms, and addressing any underlying causes. Treatment options can range from conservative measures, such as increased hydration and pain management, to more invasive interventions if necessary.

It is crucial for pregnant individuals experiencing symptoms or diagnosed with hydronephrosis to work closely with their healthcare providers to ensure proper management and a healthy outcome for both the mother and the baby.

What is hydronephrosis in pregnancy?

Hydronephrosis (HN) during pregnancy is a medical condition in which there is an abnormal swelling or enlargement of one or both kidneys due to the accumulation of urine. This condition typically occurs as a result of an obstruction in the urinary tract, hindering the normal flow of urine from the kidneys to the bladder. The physiological changes that accompany pregnancy, such as hormonal fluctuations and the physical pressure exerted by the growing uterus, can contribute to the development of hydronephrosis in expectant mothers.

The primary cause of hydronephrosis during pregnancy is often the compression of the ureters—the tubes that carry urine from the kidneys to the bladder—by the expanding uterus. This compression can lead to a backup of urine, causing the affected kidneys to swell.

Symptoms of hydronephrosis during pregnancy may include pain or discomfort in the lower abdomen or back, increased frequency of urination, and susceptibility to urinary tract infections. In certain instances, hydronephrosis can be asymptomatic and only identified through routine prenatal screenings.

Managing hydronephrosis during pregnancy involves closely monitoring the condition, addressing any symptoms, and tackling the underlying causes when possible. Treatment approaches can vary, ranging from conservative measures like increased hydration and pain management to more invasive interventions if required.

It is crucial for pregnant individuals experiencing symptoms or diagnosed with hydronephrosis to work closely with their healthcare providers to ensure appropriate management and a healthy outcome for both the mother and the baby.

Causes of hydronephrosis in pregnancy

Hydronephrosis during pregnancy can result from a combination of anatomical and physiological changes associated with pregnancy. The primary causes include:

• Ureteral Compression: As the uterus expands during pregnancy, it can exert pressure on the ureters—the tubes that carry urine from the kidneys to the bladder. This compression may lead to a partial or complete blockage of urine flow, resulting in hydronephrosis.
• Hormonal Changes: Hormonal fluctuations during pregnancy, particularly the increased levels of progesterone, can cause relaxation of smooth muscles, including those in the urinary tract. This relaxation can contribute to a slowdown in urine transport, making pregnant women more susceptible to hydronephrosis.
• Increased Blood Flow: The increased blood volume and flow to the kidneys during pregnancy can contribute to the dilation of the renal pelvis and ureters. This dilation, combined with external pressure from the growing uterus, can lead to hydronephrosis.
• Physiological Changes: Pregnancy-related changes in the position and orientation of the urinary tract organs can also play a role in the development of hydronephrosis.
• Pre-existing Conditions: Certain pre-existing conditions, such as kidney stones, urinary tract infections, or abnormalities in the urinary system, can increase the risk of hydronephrosis during pregnancy.

It’s important to note that hydronephrosis can vary in severity and may affect one or both kidneys. While mild cases may not cause noticeable symptoms, more severe cases can lead to pain, discomfort, and complications. Pregnant individuals experiencing symptoms or those at risk for hydronephrosis should consult with their healthcare providers for proper diagnosis and management.

Is hydronephrosis during pregnancy physiologic?

Hydronephrosis during pregnancy is typically considered a physiological adaptation rather than a pathological condition. The term “physiologic hydronephrosis” is often used to describe the normal dilation of the renal pelvis and ureters that can occur in pregnant women.

Several factors contribute to the development of hydronephrosis during pregnancy:

• Uterine Compression: As the uterus expands to accommodate the growing fetus, it can exert pressure on the adjacent structures, including the ureters—the tubes that carry urine from the kidneys to the bladder. This compression can lead to a temporary dilation of the renal pelvis and ureters.
• Hormonal Changes: Hormonal fluctuations during pregnancy, particularly the increased levels of progesterone, can cause relaxation of smooth muscles, including those in the urinary tract. This relaxation contributes to a slowing down of urine transport and may result in dilation.

While physiologic hydronephrosis is a normal and expected adaptation to pregnancy, it’s essential to differentiate it from pathologic hydronephrosis, which may occur due to obstructions or other underlying conditions that are not part of the normal physiological changes associated with pregnancy.

When is hydronephrosis common during pregnancy?

Hydronephrosis during pregnancy is most common during the second and third trimesters. This is because as the pregnancy progresses, the uterus expands in size, reaching its maximum size during these later stages. The enlarging uterus can put pressure on the ureters, the tubes that carry urine from the kidneys to the bladder, leading to obstruction and subsequent dilation of the renal pelvis and ureters.

In the first trimester, the uterus is relatively smaller, and hydronephrosis is less likely to occur. However, as the uterus grows and occupies more space in the abdominal cavity, it can exert pressure on the urinary tract, potentially causing the dilation of the renal structures.

It’s important to note that not all pregnant individuals will experience hydronephrosis, and the severity can vary. Additionally, some women may not have noticeable symptoms even if hydronephrosis is present. Regular prenatal care, including monitoring for any signs or symptoms of urinary tract issues, is essential during pregnancy. If there are concerns or symptoms suggestive of hydronephrosis, healthcare providers may use imaging studies, such as ultrasounds, to assess the condition and determine the appropriate course of action.

Symptoms

Hydronephrosis during pregnancy can manifest with various symptoms, and these may vary in severity. Some pregnant individuals may experience mild or no symptoms at all, while others may notice more noticeable signs. Common symptoms of hydronephrosis during pregnancy include:

• Flank Pain: Pain or discomfort in the side or back, typically on one side, is a common symptom. This pain may be constant or intermittent and can range from mild to severe.
• Abdominal Discomfort: Some individuals may feel a sense of fullness or discomfort in the abdominal area.
• Frequent Urination: Hydronephrosis can lead to increased pressure on the bladder, causing pregnant women to feel the need to urinate more frequently.
• Urinary Tract Infections (UTIs): The backup of urine can increase the risk of urinary tract infections, which may present with symptoms such as pain during urination, urgency, and frequency.
• Nausea and Vomiting: In more severe cases, hydronephrosis may cause nausea and vomiting.
• Blood in Urine: Hematuria, or the presence of blood in the urine, can occur in some cases.

It’s important to note that symptoms can vary, and some individuals may not experience any noticeable signs. Additionally, the severity of symptoms may depend on the degree of hydronephrosis and whether it affects one or both kidneys.

If a pregnant woman suspects she has hydronephrosis or experiences any concerning symptoms, it is crucial to seek prompt medical attention. Proper diagnosis and management are essential to ensure the well-being of both the mother and the developing fetus. Healthcare providers may conduct imaging studies, such as ultrasounds, to assess the kidneys and urinary tract and determine the appropriate course of action.

Diagnosis

The diagnosis of hydronephrosis during pregnancy typically involves a combination of clinical assessment, medical history review, and imaging studies. Here are the common steps in diagnosing hydronep rosis during pregnancy:

• Clinical Assessment: Healthcare providers will review the patient’s medical history, including any pre-existing kidney conditions, urinary tract infections, or previous occurrences of hydronephrosis.
  • Symptoms such as flank pain, abdominal discomfort, frequent urination, or blood in the urine will be discussed and evaluated.
  • Physical Examination: A physical examination may be conducted to assess the abdomen for tenderness or swelling.
  • Laboratory Tests: Urinalysis may be performed to check for signs of urinary tract infection (UTI) or blood in the urine.
  • Imaging Studies:

1. Ultrasound: This is a common and non-invasive imaging technique used to visualize the kidneys and urinary tract. It can help identify any dilation or obstruction in the urinary system.
2.  MRI (Magnetic Resonance Imaging) or CT (Computed Tomography) Scan: In some cases, especially when additional details are needed, these imaging studies may be recommended. However, they are often used with caution during pregnancy, particularly in the first trimester.

• Renal Scintigraphy: This nuclear medicine imaging technique may be employed to assess kidney function and identify any abnormalities.
  • Invasive Procedures (if necessary): In some cases, particularly if there is a need for more detailed information or if intervention is being considered, additional procedures like a retrograde pyelogram or cystoscopy may be performed.

It’s essential for pregnant individuals experiencing symptoms or at risk for hydronephrosis to communicate openly with their healthcare providers. The choice of diagnostic tools and procedures will depend on the specific circumstances of the pregnancy, the severity of symptoms, and the need for further evaluation. Early diagnosis and appropriate management are crucial to ensure the well-being of both the pregnant individual and the developing fetus.

Treatment of hydronephrosis during pregnancy

The treatment of hydronephrosis during pregnancy depends on the severity of symptoms, the underlying cause, and the impact on the health of both the pregnant individual and the developing fetus. Here are some common approaches to managing hydronephrosis during pregnancy:

• Close Monitoring: In mild cases without significant symptoms, healthcare providers may opt for close monitoring through regular check-ups, ultrasounds, and urine tests.
  • Pain Management: Over-the-counter pain relievers may be recommended to alleviate discomfort or pain associated with hydronephrosis. However, it’s important to consult with a healthcare provider before taking any medications during pregnancy.
  • Hydration: Adequate hydration is essential to help maintain urine flow and reduce the risk of urinary tract infections. Pregnant individuals are often advised to drink plenty of water.
  • Antibiotics: If there is evidence of a urinary tract infection, antibiotics may be prescribed to treat the infection and prevent complications.
  • Positional Changes: Adjusting body positions, such as lying on one side, may help relieve pressure on the ureters and improve urine flow.
  • Catheter Placement (in severe cases): In rare and severe cases where there is a complete obstruction, a ureteral stent or nephrostomy tube may be inserted to temporarily relieve the blockage and allow urine to drain.
  • Surgical Intervention (in specific cases): In instances where the obstruction is persistent and poses a significant risk to the health of the mother or the fetus, surgical intervention may be considered. However, this is usually a last resort and is carefully weighed against potential risks to the pregnancy.

It’s crucial for pregnant individuals with hydronephrosis to work closely with their healthcare providers. The chosen treatment approach will consider the individual circumstances, the stage of pregnancy, and the potential impact on both maternal and fetal health. Regular follow-ups and communication with the healthcare team are essential to monitor the condition and adjust the treatment plan as needed.

Conclusion

In conclusion, hydronephrosis during pregnancy is a condition characterized by the abnormal swelling or enlargement of one or both kidneys due to the accumulation of urine. This phenomenon is often a result of the anatomical and physiological changes associated with pregnancy, such as the compression of ureters by the growing uterus, hormonal fluctuations, and increased blood flow to the kidneys.

While some cases of hydronephrosis may be asymptomatic or cause only mild discomfort, others can lead to significant pain, urinary symptoms, or complications. The diagnosis involves a combination of clinical assessment, medical history review, and imaging studies, with ultrasound being a common and safe choice during pregnancy.

The management of hydronephrosis during pregnancy varies depending on the severity of symptoms and the underlying cause. Conservative measures such as close monitoring, pain management, and hydration are often employed. In more severe cases, antibiotics, positional changes, or, rarely, surgical interventions may be considered.

Regular communication and collaboration between the pregnant individual and their healthcare providers are crucial for effective management and the overall well-being of both the mother and the developing fetus. Early diagnosis and appropriate interventions can contribute to a positive outcome, ensuring a healthy pregnancy and delivery for the expectant mother.

In most cases, physiologic hydronephrosis during pregnancy is temporary and resolves after childbirth. It typically does not cause significant symptoms or complications. However, if symptoms are severe or if there are concerns about the possibility of an underlying pathology, healthcare providers may conduct further assessments and interventions to ensure the well-being of the pregnant individual and the developing fetus.

Prof. Dr. Emin ÖZBEK

Urologist

Istanbul- TURKEY