Baby gains about 1/2 to a pound a week. Most don't gain a whole lb but it is normal to gain around 1/2 lb each week. If baby is 8.5 now it may be 9.5 at 39 weeks. Great going its so awesome nice big healthy baby. I hope baby comes soon for you, I have such a long weight.
Wow big girl good luck I hope you deliver by 39 weeks also