Adams, whose best effort was her third throw of 19.25m, was unable to top that, leaving Carter with one throw to win gold. She did it with a brilliant 20.21m, an American record, and best throw of the year.
That third throw had Adams' excitedly hopping on the spot, knowing it was a quality heave. However Carter went six centimetres past her moments later and then had a final ace in her back pocket. Marton's effort meant Carter had to play it to secure victory.
It is Adams' fifth world indoor medal, to go with three golds and a silver, and it is the first time she's been eclipsed in a major international meet since 2010.
''It's good to be competing at international level with these girls, it's very exciting. But Rio is the big picture," Adams said of August's Olympics.
Her coach Jean-Pierre Egger estimates Adams requires about 10 percent improvement to be a big chance in Rio.
''If we are to go over 20m, it's a must for us," he said yesterday.
Of the result, Egger said ''it's okay, it's not a bad performance. It shows us realistically what we have to do until Rio. It is a good test to see we are not ready, we have much to do, and we will do it."
Adams is relishing the challenges to come. Her rationale is straightforward.
''I know I still have more in me. It's just a matter of getting out and getting more competitions under my belt and working on that confidence in competition at international level."
Her medal is New Zealand's second at the world indoor champs, after men's shot putter Tom Walsh won gold 24 hours earlier.
New Zealand's competition ends this morning with Nick Willis competing in the 1500 final.
