NEW YORK (Bloomberg) — The worsening US economy is leading more Americans to curtail saving for retirement, a new TD Ameritrade Holding Corp. study said.

The economy was cited by 50 percent of those who said they had stopped or reduced contributions to their retirement plans, said TD Ameritrade, an online brokerage. Unemployment and the cost of health care were other common reasons, cited, respectively, by 32 percent and 25 percent of people surveyed.

Pressure on retirement account funding is expected to grow, as fewer US employers offer traditional pension plans and the federal government struggles to shore up Social Security's long- term finances. General Motors Corp. will suspend company 401(k) retirement plan matching payments for nonunion employees beginning November 1.

"It's not a time for people to stop contributing," said Diane Young, director of retirement and goal planning at Omaha, Nebraska- based TD Ameritrade said in an interview. "Because time is money, it's important to stay on track."

Even if consumers feel they need to reduce contributions to make ends meet, it's a good time to review retirement plans to make sure their assets are allocated properly, Young said.

The telephone survey of 1,005 US adults was conducted by Opinion Research Corp. from September 11-14. It has a margin of error of plus or minus three percent.

Overall, 46 percent of those surveyed said they weren't putting any money into a retirement plan. Of those with a plan, one in three, or 34 percent, including those over the age of 65, said they have less than $50,000 invested, compared with 21 percent who said they had more.