We are on week 3 of BLW and my 8 month old is constipated. I gave her prune juice. She's eating a lot of fruits and veggies so I didn't think we'd have this issue? What else shall I try?

If she is eating a lot of fruits and vegetables, you can try increasing her fluid intake to help "move things along" (pardon the lack of better descriptors).

lots of water, breastmilk and P foods may help relieve: pears, prunes, papaya, peaches, plums, apricot