I had this too although my situation was a bit different because it wasn't diagnosed until I went over 40 weeks and started being monitored via u/s. It wasn't picked up at the 20 week scan probably cause it wasn't there then.

DS was born at 41+4 after going into labour naturally. He was 8 pound 7 ounces. I did have a lot of fluid and will never forget the initial relief when they broke my waters.

I don't think my case was severe, I was large, tight and uncomfortable but it was Feb when the Vic bushfires happened. Everyone was hot.

I don't want to freak you out but I suggest you talk to your care provider about the risk of PPH. I had a fast, heavy bleed right after ds was born and they told me later the polyhydramnios was to blame. The uterus is overstretched and can't contract quick enough when the placenta detached. At least, that's what they told me.

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