Spotlight on Fetal Hydronephrosis During Pregnancy

 

One of the most frequently observed conditions during pregnancy ultrasounds is fetalhydronephrosis. It is the oedema or enlargement of the kidneys of an unborn child as a result of excess urine. Although the diagnosis can be worrying for expecting parents, in most instances, the condition heals itself and does not indicate severe complications. Understanding what fetal hydronephrosis is, its causes, and how it is managed can help guide parents through the process with clear information and confidence.

What Is Fetal Hydronephrosis?

Fetal hydronephrosis is a condition that arises when urine cannot drain out of the kidney into the bladder, leading to swelling of the kidney. This is normally identified during a routine prenatal ultrasound, typically between 18 and 22 weeks of pregnancy. The classification depends upon how much the renal pelvis (the section of the kidney where the urine gathers) is dilated. Milder cases can either resolve before or after birth, whereas the severe ones may need medical care following delivery.

Fetal Hydronephrosis Causes

Fetal hydronephrosis can be caused by a number of factors. The most prevalent reasons are:

●     Ureteropelvic Junction (UPJ) Obstruction: This occurs when the kidney and the ureter are not properly connected, preventing normal urine flow.

●     Vesicoureteral Reflux (VUR): A condition in which urine flows backwards from the bladder into the kidneys.

●     Posterior Urethral Valves (PUV): A condition that affects male fetuses, involving the growth of abnormal tissues in the urethra that restricts urine flow.

●     Physiological Hydronephrosis: In most instances (particularly mild ones), the swelling is temporary and results from normal changes during fetal development.

How Is It Diagnosed?

Prenatal ultrasound is primarily used to make the diagnosis. The physician measures the size of the renal pelvis and monitors it throughout the pregnancy. If the dilation seems significant or progresses, further ultrasounds or specialised scans may be prescribed to check kidney function and bladder health.

In some instances, a postpartum ultrasound helps determine whether the condition has cleared or requires further management. In certain cases, tests such as a voiding cystourethrogram (VCUG) or a renal scan may be recommended to evaluate urinary flow and kidney function.

Treatment and Management

The majority of fetal hydronephrosis cases do not necessitate immediate intervention during pregnancy. Monitoring—particularly through regular ultrasounds that track kidney development and detect changes—is key. If the swelling does not disappear after birth or worsens, a pediatric urologist may recommend additional examinations and treatments.

Treatment varies depending on the cause and severity. Mild cases often resolve naturally as the baby grows. Moderate to severe cases may require antibiotics to prevent urinary tract infections, or in rare situations, surgical procedures to correct obstructions or repair reflux.

Outlook and Prognosis

The outlook for fetal hydronephrosis is generally very good. Most mild cases—around 70–80%—resolve spontaneously without long-term kidney damage. Prenatal screening allows early detection, enabling healthcare providers to monitor and manage the condition effectively, minimising risks to the baby’s health.

Final Thoughts

Fetal hydronephrosis may sound like a frightening condition, but advancements in prenatal imaging and pediatric care have made it highly manageable. With consistent monitoring, early assessment, and appropriate medical treatment, most affected babies go on to lead normal lives with healthy kidney function. Awareness and education remain essential to reducing parental anxiety and ensuring the best possible outcomes for both mother and baby.