Im 39 wks and 4days, my doctor told me if my hands, arms, face, etc start to swell and they hadn't before that i should go to the hospital since it's common for ftms to have preeclampsia. Drink plenty of water and call your doc to make sure.
As long as your blood pressure isnt up then its normal in your 3rd trimester im 38+1 and have had really bad swelling since last friday. To the point it hurts to walk and bend my feet and fingers even my legs swell up to my knees.
I would call your Dr or midwife. Bit in the mean time drink plenty of fluids and lay down, put your feet up above your heart.