Awww. I'm sure you can get this under control before baby comes! Especially if you have a trainer/behaviorist working with you.
Lucy gets a little possessive with her food bowl but that's mainly with our other dog.
Has your trainer mentioned Nothing in Life for Free? I love that training program; it's just an all-around, very gentle way of reinforcing who is in charge.
That's about all I have to offer other than my best wishes.
Nothing in Life is Free