Polyhydramnios

Hey y’all! I’m 34 weeks 3 days and at a checkup ultrasound on Tuesday I was told I have a moderate case of polyhydramnios. They say it’s generally caused by gestational diabetes, but I’ve passed 2 of the 1 hour tests with flying colors and my A1C is perfect. The other causes are due to a possible infection that’s impacting the baby, or maybe preeclampsia. They ran some blood work for both.

Has anyone else had this diagnosis? What was your experience, and what caused it?