This sounds crazy but being a mother, I know what I'd want.
Don't get her anything involving the baby. Make it just for her because once Lava Girl is born, all the attention will be drawn to her and not Amber. As corny as it sounds maybe something like a huge set of bubble baths, bath crystals, bath oil beads, lotions, and body spray. Being pregnant takes a toll on a woman's body and one of the best things to do is to take a nice long relaxing hot bath.... oh and add some candles to it too. Give her a couple of homemade coupons for "Entitled to a long bath w/o kitties" or "Pamper yourself time"... things that involve the bubbles, lotions and other things. DH did this for me one time and I loved it SO much!
Oh and another good coupon can be things like "One night of alone time w/o the baby"... "A couple hours of shopping w/o baby" and to make it fun, "Redeemable for not having to change a REALLY REALLY bad diaper"
I've got TONS of ideas for them!