Multi cystic dysplastic kidney (MCDK)


What is it?

A Multi Cystic Dysplastic Kidney (MCDK) is a kidney that has not developed normally in the womb. One of the baby’s kidneys has become enlarged, with varying sizes of fluid filled spaces or cysts within it (multicystic) and hence has not formed properly (dysplastic).

The cysts cause the affected kidney not to function. Over time this affected kidney will shrink and may disappear.

The normal kidney will do the work for both kidneys.

Where are the kidneys?

The kidneys are bean shaped organs at the bottom of the rib cage at the back of the body.

What do the kidneys do?

Some functions are:

  • Remove waste products
  • Maintain normal blood pressure
  • Filters the blood and forms the urine.

The urine flows from the kidneys through the ureters to the bladder and from here passes through the urethra to the outside of the body.

Picture of MCDK


What happens next?

You will be able to discuss the scan findings with the Fetal Medicine Midwife or an appropriately trained professional.

You will be referred to the Fetal Medicine Clinic where you will be  given an appointment to have a further scan and a more detailed discussion with the Consultant Obstetrician.


Regular scans will be arranged to assess the healthy kidney and the urinary system. A check on baby’s growth and amniotic fluid will be carried out too.

The amniotic fluid is made up of the urine produced by the kidney

You will be referred to a neonatologist (doctor who cares for babies) during pregnancy so they will be aware of baby’s condition before delivery.

After Delivery

Baby will be given a full examination by the neonatologist before going home.

Your baby will need a renal (kidney) scan to confirm the diagnosis and check the healthy kidney. This is usually performed after discharge from hospital.

An appointment to see the Paediatric Nephrologist will be arranged.

Future Outlook

Most babies with only one working kidney have no complications and do not need treatment. There is a slight increase in developing urine infections and high blood pressure.

The long-term outlook for isolated unilateral MCDK is excellent.


It can be a stressful time so if you have any questions or concerns please contact the Fetal Medicine midwife on the numbers below.

Contact Numbers

Royal Gwent Hospital 01633 234747

Nevill Hall Hospital 01873 732390 or 01873 732391

Useful Websites

ARC (Antenatal Results and Choices) - Offer information and support to parents who are making decisions before, during and after tests in pregnancy

Tel no: 084507722990


Email: info@arc-uk-org

ASW (Antenatal Screening Wales)


INFOKID (information for parents and carers about children’s kidney conditions)


Improving the physical and emotional health and wellbeing of expectant mothers, infants, children and young people throughout Aneurin Bevan University Health Board Area.

(N.B: The Family and Therapies team at ABUHB is NOT responsible for the content on the webpage links that we refer to in our resource sections and linked information to external sites. All information was accurate and appropriate at the time the webpage was created.)

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