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PubMed This is a summary of 18 peer-reviewed journal articles Updated
Pediatric Urology

The Modern Way: Monitoring Without Surgery

At a Glance

The modern standard of care for a multicystic dysplastic kidney (MCDK) is conservative 'watch and wait' management. Most cystic kidneys naturally shrink over time through a process called autoinvolution and only require routine monitoring with ultrasounds and blood pressure checks, avoiding surgery.

Decades ago, doctors often recommended surgery to remove a multicystic dysplastic kidney (MCDK) shortly after birth. Today, the medical consensus has shifted dramatically toward a much gentler approach: conservative management, or “watch and wait” [1][2]. Because research has shown that these kidneys rarely cause problems, most babies will never need surgery [3][4].

The Modern Approach: “Watch and Wait”

The “watch-and-wait” approach is based on the reality that a cystic kidney is essentially a passive collection of fluid that usually does not interfere with a baby’s health [2].

Why Surgery is Rarely Needed

Historically, doctors feared that leaving the non-working kidney in place might lead to high blood pressure or cancer later in life [2]. However, long-term studies have shown that these risks are extremely low [4][5]. Unless your baby develops a specific complication, nephrectomy (surgical removal of the kidney) is generally considered unnecessary [6].

Surgery is typically reserved only for:

  • Mass Effect: If the kidney is so large it pushes on the lungs or stomach, causing trouble with breathing or eating [6][7].
  • Refractory Hypertension: High blood pressure that cannot be controlled with medication [8].
  • Persistent Infection: Rare cases where the cystic kidney itself becomes a source of recurring infections [9].

The Vanishing Kidney: Autoinvolution

One of the most remarkable things about MCDK is autoinvolution. This is the process where the cysts naturally lose their fluid and the kidney begins to shrink and shrivel [3][10].

  • The Timeline: Shrinking often begins in the womb and continues through early childhood [11].
  • The Result: In many cases, the kidney becomes so small that it can no longer be detected on an ultrasound [3]. While this “disappearing act” happens for many, it doesn’t happen for everyone; in about one-third of cases, the kidney remains visible but small throughout life [10]. Neither outcome is considered “better”—as long as the kidney is quiet, it can stay right where it is [2].

Understanding the VCUG Test

You may hear your medical team mention a VCUG (Voiding Cystourethrogram). This is a specialized X-ray used to see if urine flows backward from the bladder to the kidneys, a condition called Vesicoureteral Reflux (VUR) [12].

In the past, every baby with MCDK had this test. Today, its use is controversial and selective [13][12]. Most doctors now believe that for an otherwise healthy baby, a VCUG is only necessary if:

  1. The healthy kidney looks abnormal or dilated on an ultrasound [13][14].
  2. The baby develops a urinary tract infection (UTI) with a fever [15][12].

If your baby’s functioning kidney looks perfect on its scans and there are no signs of infection, many experts agree that the discomfort of a VCUG can be avoided [13][16].

Your Monitoring Routine

For now, your “management” will mostly consist of two things:

  1. Periodic Ultrasounds: To watch the cystic kidney shrink and ensure the healthy kidney continues its strong growth (compensatory hypertrophy) [11][17].
  2. Blood Pressure Checks: This is a simple, non-invasive way to ensure the single functioning kidney is doing its job without straining the system [2][18].

By choosing to watch and wait, you are giving your baby’s body the chance to manage the condition naturally, while keeping surgery in reserve only if it is truly needed [2][1].

Common questions in this guide

Why is surgery rarely needed for a multicystic dysplastic kidney?
Most cystic kidneys are simply passive collections of fluid that do not harm a baby's health. Long-term studies show that complications like high blood pressure or cancer are extremely low, making routine surgical removal unnecessary in most cases.
What is autoinvolution in an MCDK?
Autoinvolution is the natural process where the cysts in an MCDK lose their fluid and the kidney shrinks over time. In many cases, the kidney becomes so small that it completely disappears from view on an ultrasound.
Will my baby need a VCUG test for their cystic kidney?
A VCUG test is no longer routinely required for every baby with MCDK. It is typically only recommended if the healthy functioning kidney looks abnormal on an ultrasound or if your baby develops a urinary tract infection with a fever.
How will my baby's MCDK be monitored?
Your baby will primarily be monitored with periodic ultrasounds to watch the cystic kidney shrink and ensure the healthy kidney is growing properly. They will also need regular blood pressure checks to make sure their functioning kidney is working without strain.
When would surgical removal (nephrectomy) be required for an MCDK?
Surgery is usually only considered if the cystic kidney is so large it pushes on the lungs or stomach, causes severe high blood pressure that medications cannot control, or becomes a source of recurring infections.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Why is the 'watch-and-wait' approach safer for my baby than removing the kidney?
  2. 2.Does the healthy kidney currently show enough compensatory growth that we can feel confident in its function?
  3. 3.How often will we need to check my baby's blood pressure, and what are the 'normal' ranges for an infant?
  4. 4.If the cystic kidney does not shrink (autoinvolute), does that change our long-term plan?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (18)
  1. 1

    The Outcome of Multicystic Dysplastic Kidney Disease Patients at King Abdulaziz Medical City in Riyadh.

    Alamir A, Al Rasheed SA, Al Qahtani AT, et al.

    Cureus 2023; (15(4)):e37994 doi:10.7759/cureus.37994.

    PMID: 37223165
  2. 2

    Clinical outcome of children with prenatally diagnosed isolated unilateral multicystic dysplastic kidney.

    Huettinger M, Bogner G, Fischer T, et al.

    European journal of obstetrics, gynecology, and reproductive biology 2025; (312()):114112 doi:10.1016/j.ejogrb.2025.114112.

    PMID: 40517513
  3. 3

    Multicystic renal dysplasia, a histomorphological spectrum: Seven years experience from a tertiary care hospital.

    Gupta K, Mandal S, Mallya V, et al.

    Indian journal of pathology & microbiology 2024; (67(2)):385-389 doi:10.4103/ijpm.ijpm_202_23.

    PMID: 38427756
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    Multicystic dysplastic kidney (MCDK) in the neonate: The role of the urologist.

    Psooy K,

    Canadian Urological Association journal = Journal de l'Association des urologues du Canada 2016; (10(1-2)):18-24 doi:10.5489/cuaj.3520.

    PMID: 26977201
  5. 5

    Renal function in children with a congenital solitary functioning kidney: A systematic review.

    Hutchinson KA, Halili L, Guerra A, et al.

    Journal of pediatric urology 2021; (17(4)):556-565 doi:10.1016/j.jpurol.2021.03.001.

    PMID: 33752977
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    Neonatal multicystic dysplastic kidney with mass effect: A systematic review.

    Pettit S, Chalmers D

    Journal of pediatric urology 2021; (17(6)):763-768 doi:10.1016/j.jpurol.2021.09.003.

    PMID: 34538561
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    Multicystic Dysplastic Kidney With Mass Effect in a Neonate Treated With Nephrectomy: Case Report.

    Pettit SM, Devan WJ, Chalmers DJ, Zanno A

    Urology 2021; (149()):e11-e14 doi:10.1016/j.urology.2020.11.050.

    PMID: 33309706
  8. 8

    Tubulocystic anomalies of the mesonephric duct associated with ipsilateral renal dysgenesis.

    Coleman R, Sanchez O, Ghattaura H, et al.

    Journal of pediatric urology 2019; (15(1)):46.e1-46.e6 doi:10.1016/j.jpurol.2018.07.021.

    PMID: 30446299
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    Large Multicystic Dysplastic Kidney Mimicking a Large Cystic Renal Neoplasm.

    Yadav P, Sureka SK, Ansari MS, et al.

    Journal of clinical and diagnostic research : JCDR 2017; (11(5)):PD03-PD04 doi:10.7860/JCDR/2017/24226.9887.

    PMID: 28658845
  10. 10

    Multicystic dysplastic kidney - treat each case on its merits.

    Faruque A, Narayanan S, Marley I, et al.

    Journal of pediatric surgery 2020; (55(11)):2497-2503 doi:10.1016/j.jpedsurg.2019.12.008.

    PMID: 31987520
  11. 11

    Natural History of Contralateral Hypertrophy in Patients with Multicystic Dysplastic Kidneys.

    Gaither TW, Patel A, Patel C, et al.

    The Journal of urology 2018; (199(1)):280-286 doi:10.1016/j.juro.2017.06.075.

    PMID: 28645868
  12. 12

    Knowledge of vesicoureteral reflux obtained by screening voiding cystourethrogram in children with multicystic dysplastic kidney does not change patient management or prevent febrile urinary tract infection.

    Brown C, McLeod D, Ching C

    Journal of pediatric urology 2019; (15(3)):267.e1-267.e5 doi:10.1016/j.jpurol.2019.03.013.

    PMID: 30992197
  13. 13

    Voiding Cystourethrogram in Children With Unilateral Multicystic Dysplastic Kidney: Is It Still necessary?

    Blachman-Braun R, Camp MM, Becerra MF, et al.

    Urology 2020; (139()):156-160 doi:10.1016/j.urology.2020.02.005.

    PMID: 32081673
  14. 14

    Necessity of performing voiding cystourethrography for children with unilateral multicystic dysplastic kidney.

    Yamamoto K, Kamei K, Sato M, et al.

    Pediatric nephrology (Berlin, Germany) 2019; (34(2)):295-299 doi:10.1007/s00467-018-4079-z.

    PMID: 30255447
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    Update on Multicystic Dysplastic Kidney.

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    Current urology reports 2015; (16(10)):67 doi:10.1007/s11934-015-0541-7.

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  16. 16

    The importance of a correct timing of kidney ultrasound in patients with congenital solitary kidney.

    Klain A, Guarino S, Di Sessa A, et al.

    Journal of clinical ultrasound : JCU 2022; (50(6)):843 doi:10.1002/jcu.23239.

    PMID: 35611580
  17. 17

    The Incidence and Durability of Compensatory Hypertrophy in Pediatric Patients with Solitary Kidneys.

    Wang MK, Gaither T, Phelps A, et al.

    Urology 2019; (129()):188-193 doi:10.1016/j.urology.2019.04.003.

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  18. 18

    Conservative Management of Segmental Multicystic Dysplastic Kidney in Children.

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This information about multicystic dysplastic kidney management is for educational purposes only and does not replace professional medical advice. Always consult your pediatric nephrologist or urologist to determine the best monitoring plan for your child.

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