Hey hun

My last little man had the same thing show up at 19 weeks. His was bilateral though. Measurements were the same as yours from memory.
My understanding was that this can be a fairly common finding, which often resolves during the rest of the pregnancy. You're right, another ultrasound is performed. We had a repeat one done at 30 weeks which showed everything looked normal. So don't worry!
I think they used to give antibiotics to some of the babies who showed this in utero, but apparently recent studies in the last few years shows that this is probably not needed. Sometimes they might also like to do an ultrasound after the baby has been born to check again, but if the problem seems to have resolved there's no real need to do that either. Just keep an eye out for any signs of an infection etc.

Our paed decided initially there was no need to do an ultrasound after he was born, but we ended up having one a few weeks ago only because our fella has another health problem and has been having everything checked out.

I'm sure everything will be all fine with your little one. All the best!