I have heard you get an eternity ring for first anniversary or first baby.

DH and I have been married for almost 4 yrs and I am now carrying his 4th child... I'm still waiting for my eternity ring.
DH keeps telling me he will get me one eventually... I think I am entitled to at least a maternity ring! lol
I have a beautiful wedding ring with 10 princess cut diamonds in it... I want another like it for my eternity/maternity ring.