Democratic presidential candidate Hillary Clinton struggled to answer a question at Sunday night's town hall about the rising costs of health care after the passage of Obamacare, telling a woman to keep shopping around.

Teresa O'Donnell, an office manager in Ohio, told Clinton about how her monthly costs for health care insurance for her family of four went from $490 to $1,081 a month.

"I know Obama told us that we'd be paying a little more. But doubling, over doubling, my health insurance cost has not been ‘a little more.’ It has been difficult to come up with that kind of payment every month. I would like to vote Democratic, but it's cost me a lot of money, and I'm just wondering if Democrats really realize how difficult it's been on working-class Americans to finance Obamacare?" O'Donnell asked.

Clinton and O'Donnell discussed by what means the insurance was purchased.

"So you were going to a broker and buying a health insurance policy? And in effect, it nearly tripled after you went onto the exchange and bought a policy under the Affordable Care Act? Is that right?" Clinton asked.

"We could not do that. It was much more expensive than just purchasing private insurance from an insurance company," O'Donnell said.

"So you're still buying the private insurance directly?" Clinton said.

"Yes," O'Donnell said.

"OK, well, first of all let me say, I very much want to get the cost down and that is going to be my mission because I do think that for many, many people, but there are exceptions, like what you're telling me, having the Affordable Care Act has reduced cost, has created a real guarantee of insurance, because if you'd had a pre-existing condition under the old system you wouldn't have gotten affordable insurance, so it's done a lot of really good things, but it has become increasingly clear that we're going to have to get the cost down," Clinton said.

Clinton later recommended to O'Donnell to keep shopping.

"And one thing that I would like you to do, and I'm not saying it's going to make a difference, but I would like you to just go shopping on that exchange," Clinton said.

The Affordable Care Act for many, including O'Donnell, has resulted in increased insurance costs and loss of coverage altogether, although Clinton has been trying to tie herself to it and President Obama's policies on the campaign trail.