Low amniotic fluid?

Was anyone told around 35 weeks that your fluid was low? If so, what was the outcome? Had a biophysical profile done today due to decreased fetal movement and they found that my fluid is low...5th percentile to be exact. OB said it's concerning, but just needs to be monitored. I go back in 2 days to have it checked again. I've had ultrasounds every few weeks and it's been fine until now so just not sure what happens from here on out. Thanks mamas :)