Fluid on kidneys?

Natalie • July 21 💚 Feb ’20 💙 March ‘18 💙 Dec ‘15 💙🧩 4 miscarriages 🌈
Just finished my anatomy scan - the tech said they would need to follow up (probably at 28w) because she found fluid on the kidneys.  Anyone have a similar experience?  What might this indicate?  My dr is doing a c-section now so I have to come back to see him to discuss the US in a few hours.  Feeling a little uneasy.  Thank you.