Fetal Kidney Cysts Found at 20 Week Ultrasound


Dear Ms. Ultrasound,
At my 20 week ultrasound the doctor told us that there were multiple cysts on the baby's left kidney with the largest cyst measuring 1.5 cm. She is sending us to a perinatologist to look into this further.

This is our first child and I am terrified. Other than the cysts, she said our baby is measuring 6 days ahead of schedule. I hope that is a good thing.

Please help me understand the cysts, how they came about, if they can be removed, what the prognosis is. We cannot get into the perinatologist until 24 weeks, I called to try to get on a waiting list and the doctor said it would be fine to wait until 24 weeks. Please help!


What you may be talking about is called Multicystic dysplastic kidney (MCDK).

This is the most common growth found on a fetal kidney. The condition has a two to one male predominance and usually is present in only one kidney. When the other kidney is normal, the prognosis is good, even if the kidney with the cysts is completely nonfunctional! As long as the amniotic fluid level is normal at least one of the kidneys is functioning well.

It sounds like the baby was fine except for the one kidney from the report you got from your doctor.This goes along with the good prognosis statistics.

I know how scary this kind of finding is on a Mommy to be, but I think things will be fine with your baby.

If you have any further questions after you have seen the perinatologist please let me know.

With regards,
-- Jane RDMS

Jane Foley

Jane Foley has worked as a Sonographer (Ultrasound Technologist) since 1979. Jane has lived and worked in many parts of the world including Saudi Arabia. She is a Registered Diagnostic Medical Sonographer or RDMS. She pulls a wealth of information from her experience in the field of Radiology and her interactions with such a broad cross-section of cultures she has visited. She now makes her home on the island of Maui with her English husband, Michael.