SAUGUS – If you’re looking to buy a new mattress, don’t head for the nearest Mattress Discounters store, a nationwide retail chain with sleep centers on the North Shore in Saugus, Danvers and Beverly.The company plans to close 48 stores in New England because its operations in the region are losing millions of dollars while the company seeks bankruptcy protection, according to court records.The retailer, based in Upper Marlboro, Md., is seeking Chapter 11 protection from the U.S. Bankruptcy Court in its home state. Plans to close its New England branches in Rhode Island, Massachusetts and New Hampshire were detailed in court filings made Wednesday.The New England stores, which the company refers to as sleep centers, will be closed in three to six weeks, a Mattress Discounters representative said in a written statement.The firm blames its current sales trouble on an industry downturn, heightened competition and a weak economy. The New England stores lost $1.5 million last year and about $2.9 million this year. Besides exiting the New England market, Mattress Discounters’ turnaround plans include reducing some of its retail operations in the Mid-Atlantic and possibly selling its manufacturing business.Mattress Discounters owes about $16.5 million to its lenders and about $10 million to other creditors. The company has 140 stores and has been in business for nearly 30 years. It has 475 full- and part-time employees in six states in the Northeast.According to Reuters, Mattress Discounters operated 240 stores when it first filed for bankruptcy in 2002, had closed and sold several sleep centers, and exited from the bedding markets in California and Michigan, allowing it to emerge from bankruptcy protection in 2003.Last year, Houston, Texas-based Mattress Firm had intended to acquire the company, but the deal fell apart.Mattress Discounters’ sleep centers near Lynn include 1373 Broadway in Saugus; 189 Endicott St. in Danvers; 1074 Revere Beach Parkway in Chelsea; and 53 Dodge St. in Beverly.A call Friday to Darrell Slane, manager of real estate at the corporate headquarters, seeking a more specific timetable for closure of the North Shore stores, was not immediately returned.