President Obama’s campaign raised far less money in January than it did during the same month four years ago, suggesting that it may have an increasingly difficult time matching his record-shattering financial numbers from 2008.

Obama raised $29.1 million in January for his reelection campaign and the Democratic National Committee, according to disclosures filed Friday.

That number is notably lower than the $36.8 million he raised for his primary campaign in January 2008, even without any help from the national party. Obama’s campaign itself raised $11.8 million last month, disclosures show.

The amounts represent the first real downturn in Obama’s fundraising pace compared with four years ago, and follow warnings from senior campaign aides this month that Republicans and conservative groups may outspend them by November.

The numbers also underscore nagging concerns among Democrats over whether Obama can replicate the kind of grass-roots enthusiasm that swept him into office in 2008.

Michael Malbin, executive director of the Campaign Finance Institute, noted that the Obama campaign would have to raise nearly $50 million per month until November to match the $745 million he raised in 2008 — and the earlier total came without the help of the DNC.

“To get to $750 million, or even $1 billion as some have suggested, becomes a very, very hard climb from here,” Malbin said. “There’s been concern about the enthusiasm level and maybe this is part of it . . . This is a very big drop and something the campaign has to be concerned about.”

There are many caveats, including the fact that Obama raised about $300 million in the last two months of the 2008 contest. Obama also does not have an epic primary fight to drive donations, as he did with then-senator Hillary Rodham Clinton, nor does he have to spend money on such a contest.

Indeed, the Obama campaign reports having $76 million in cash on hand at a time when Mitt Romney and other Republican presidential candidates are spending money as fast as they bring it in.

“We’re not in the midst of a competitive primary and are putting this general election money away in the bank, while investing some of it an organization on the ground the GOP doesn’t dream of matching,” said one senior campaign aide, who requested anonymity in order to discuss election strategy. “The Republicans are raising primary money, and they are spending whatever they raise.”

That’s not to say Obama hasn’t been spending big too: The campaign reports dropping $4.3 million in January just for online advertising.

Romney and other Republican presidential candidates, along with the parties and many super PACs, have until Monday night to file their January fundraising disclosures with the Federal Election Commission. The results will provide revealing clues about the financial standing of candidates such as Romney, who has had to spend more than he expected in a tight race, and rival Rick Santorum, who until recently has raised very little.

Whether or not he’s on track to match his 2008 numbers, Obama still shows an ability to raise money matched by few modern politicians. He continues to do particularly well among supporters who give less than $200, which accounts for close to half of his total once repeat donors are taken into account.

Since announcing his reelection effort last year, Obama has raised more than $250 million for his campaign and the DNC. The January figures are slightly higher than the $27.2 million raised by President George W. Bush and the Republican National Committee during the same period in 2004, when Bush was running for reelection.

But Obama campaign officials have recently acknowledged fears that their monetary advantage won’t last, pointing to Romney’s fundraising strength on Wall Street and the rise of wealthy conservative groups to help the GOP nominee. Last week, the president reversed himself by agreeing to endorse the efforts of a super PAC called Priorities USA Action, which can accept unlimited corporate and individual donations.

In a sign that the financial pressure is mounting, Obama spent a good part of his trip to the West Coast this week at a series of fundraisers, including stops in Los Angeles, San Francisco and Seattle.