The Hollywood Reporter said Thursday Neuwirth plans to leave the show this summer after 15 months.
Nathan Lane, who originated the role of Morticia's husband, Gomez, in the show last year, left in mid-March.
Roger Rees, who like Neuwirth once co-starred on TV's "Cheers," took over the role of Gomez when Lane left.
Shields's Broadway credits include "Chicago," "Cabaret," "Grease" and "Wonderful Town."
Dennis Rodman pledges to end trips to North Korea
Scarlett Johansson steps out with fiance after pregnancy reveal