The poll sampled 1,205 likely voters in the state and has a margin of error of plus or minus 2.8 percentage points. The survey was conducted Oct. 1-5 and came after the first presidential debate and Trump’s coronavirus infection, adding to the list of recent polls that showed the president losing ground to Biden after those two major events.

Separate polls of battleground states released on Wednesday showed Biden up 5 percentage points in Wisconsin, 6 points in Nevada and essentially tied with Trump in Ohio.

Barack Obama carried Iowa and won its six Electoral College votes in both of his election victories, but the state swung hard toward Trump in 2016, when he won it by 10 percentage points over Hillary Clinton.

Other surveys conducted last month showed Trump leading in Iowa, and actually building his advantage over Biden compared with earlier polls. A Monmouth University poll released Sept. 24 showed Trump up 50 percent to Biden’s 44 percent. That poll also had the Senate race as a dead heat.

The RealClearPolitics polling average has Biden up by 1.4 percentage points over the president, and Greenfield 5 points ahead of Ernst in a closely watched contest that could determine which party controls the Senate.

Alongside Iowa, Quinnipiac also released snapshots for Pennsylvania and Florida that showed Biden ahead of Trump by double-digit margins. Biden is up 51 percent to 40 percent in Florida, and leads by an even larger margin — 54 percent to Trump’s 41 percent support — in Pennsylvania.

“In varying degrees, three critical states in three very different parts of the country come to the same ominous conclusion,” Quinnipiac polling analyst Tim Malloy said in a release. “The president’s hopes for re-election are growing dimmer by the day.”

Women are fueling much of Biden’s advantage in the three states Quinnipiac surveyed. More than 60 percent of female voters in Iowa and Pennsylvania supported the Democratic nominee, as did 56 percent of those surveyed in Florida.

The gender divide is similarly large in Iowa’s Senate race, where both major party candidates are women, with 59 percent of female respondents saying they were supporting Greenfield compared with 37 percent who were in favor of Ernst.

The polling period ended the same day — Monday — that Trump made a dramatic return to the White House from Walter Reed military hospital, likely excluding any potential bump the president may have gotten from the move.

Trump’s aides are hoping that the moment would buoy the president’s public support and jolt his flagging campaign.