Most polling suggests that Democrats should flip the House of Representatives in the midterm elections — but some analysts warned that nothing is certain a week before the pivotal contests.

“Our current hard count in the House is 212 D, 202 R, 21 toss-ups. Neither party is over 218, a majority. Democrats have the better chance to go over the top, since 20 of 21 tossups are currently held by the GOP. That doesn’t guarantee that the Democrats actually will,” Larry Sabato, head of the University of Virginia’s Center for Politics, emailed The Post on Monday.

But another analysis on Monday predicted that Democrats had an 86.4 percent chance of capturing the House, while Republicans had only a 13.6 chance of keeping their majority.

Democrats, who would need to pick up 23 seats to gain control, reportedly plan to spend $143 million on TV ads in House races, compared to about $86 million for Republicans.

And even White House officials were pessimistic about their chances, with Bill Stepien, director of political affairs, already laying the groundwork to shift blame away from President Trump should the party lose the House.

Stepien argued in an internal memo obtained by Bloomberg News that the GOP has been hindered by historical headwinds, a wave of incumbent retirements and strong fundraising by Democratic challengers.

Team Trump still sees a possible path to victory, but there’s no longer talk of what Trump predicted would be a “red wave,” in which his energized base flocked to the polls to preserve GOP control of both houses of Congress.

The president himself last publicly used the “red wave” phrase in August, the news service reported.

Sabato said it was far less likely that Democrats could win the Senate, where the GOP holds a 51-49 seat majority.

“In the Senate we currently have Rs at 50 — all they need to control with Pence — Dems at 45, with 5 toss-ups,” he said.

“For Dems to win 51, they’d have to sweep the toss-ups, and switch a GOP seat such as Tennessee or Texas. Not impossible but the equivalent of an inside straight.”

A new poll Monday by Quinnipiac University in one of the closest-watched Senate races gave Texas Republican Ted Cruz a narrow 51-to-46 percent edge over Democratic challenger Beto O’Rourke.

Trump has been campaigning furiously for GOP candidates in the weeks leading up to the Nov. 6 election, holding MAGA rallies in which he rails against the media, illegal immigrants and Democrats to fire up his base.

Democrats, meanwhile, have largely campaigned on their vow to expand health care coverage and other domestic issues.