One switch was in Iowa's 4th Congressional District. The seat had been ranked as “Solid Republican” for incumbent Tom Latham. Cook has upgraded Democratic challenger Becky Greenwald's chances, and now lists the seat as “Likely Republican.”
 
John Deeth :: Political Tipsheet Upgrades Greenwald's Chances 
The next steps up for Greenwald would be “Lean Republican,” followed by “Toss Up.”
Iowa's other four seats are rated as solid for incumbent Democrats Bruce Braley, Dave Loebsack, and Leonard Boswell, and for GOP incumbent Steve King.