Elevated amniotic fluid?

I'm 27 weeks and 2 days now. I had an ultrasound yesterday so they could check the fluid around my baby boy's kidneys. They said it normally goes away but it's been 3 months and it hasn't. Docs office called today to inform me I had elevated levels of amniotic fluid and are sending me to another hospital for a follow up. Anyone else have this issue? From what I read it could be a rare disease only 1% of women get. Could be due to diabetes (that I just tested negative for) or a birth defect.