KEENE, N.H. — Sen. Elizabeth Warren's campaign is trying to conserve cash and pulled down TV ads in Nevada and South Carolina after a disappointing third-place standing in Iowa that failed to provide a fundraising bump.

“I just always want to be careful about how we spend our money,” Warren (D-Mass.) said Wednesday after being asked about the roughly $375,000 of TV ads pulled in two states that vote later this month.

She added that her cash comes from people who make small donations. “I just want to be very careful with this money,” she said.

Warren on Wednesday also yanked an additional $100,000 worth of ads, mostly in South Carolina markets but also in Reno, Nev., according to Advertising Analytics, which tracks campaign spending on television.

Warren’s reliance on grass-roots donations — and her decision not to do a high-dollar program — has been one of her main talking points, and she has credited the decision with focusing her campaign on people rather than the powerful. But, it also means a perceived lack of momentum can cause money to dry up quickly as low-dollar donors look elsewhere.

Compounding that problem, Warren also has among the largest campaigns, with more than 1,000 on staff, meaning she has a hefty payroll bill to meet each month and little extra that she can cut before chopping personnel.

Like many candidates in the final weeks before the Iowa caucuses, Warren was spending more money than she was taking in. She had just $13.7 million in cash on hand going into January, according to her campaign filings with the federal government.

On Tuesday, Warren’s campaign canceled a flight of advertisements that were going to run on TV in Nevada and South Carolina from Feb. 17 to 23 at a cost of about $375,000, according to Advertising Analytics.

Warren still has TV time reserved in those states over the next month, according to the company. She has roughly $2 million worth of ad time set aside for those two states this month and will not be entirely dark anywhere.

Warren’s team put up a new digital ad Wednesday in New Hampshire, Nevada and South Carolina that pulls from remarks by former president Barack Obama praising Warren for spearheading the Consumer Financial Protection Bureau.

The campaign did not immediately answer questions about how much money it had put behind the new effort.

“Elizabeth understands what I strongly believe,” Obama says in the ad, “that a strong growing economy begins with a strong and thriving middle class.” Obama has not endorsed any candidate in the Democratic nomination contest.

Warren’s team alluded to money problems in a fundraising pitch Tuesday in which the campaign said that the lack of a clear result from Iowa — and the focus on how the systems there failed rather than the campaigns — had affected fundraising.

“Even though the initial numbers in Iowa look good, they’re not final,” according to the fundraising email signed by Team Warren. “And since they were announced today instead of last night, we didn’t get a big night of exciting news coverage about them (or the late-night boost in fundraising that usually comes with it).”