May 11 - Maidenform Brands Inc posted market-topping quarterly results, helped by strong sales of its shapewear products, and the intimate apparel maker raised its sales forecast for the year, sending its shares up 3 percent to their lifetime high.

'Dream' collection by Maidenform

The company, whose brands include Flexees, Lilyette and Sweet Nothings besides its namesake line, now expects 2011 sales to rise in the high single digits percentage, up from its previous outlook of a rise on the mid-to-upper single digit range.

However, Maidenform expects its gross margins to take a hit, as sales at its lower margin mass merchant segment continue to make up a larger share of revenue.

The Iselin, New Jersey-based company, which competes with Limited Brands Inc's Victoria's Secret, sees 2011 gross margins falling by 0.3-0.6 percent from 2010, down from its previous expectation of flat margins.

Maidenform reported a first-quarter net income of $14.5 million, or 62 cents a share, compared with $12.1 million, or 51 cents a share, a year ago.

Sales rose 14.5 percent to $163.6 million.

Analysts on average were expecting earnings of 57 cents a share, before special items, on revenue of $156.1 million, according to Thomson Reuters I/B/E/S.

In the latest quarter, sales of shapewear -- undergarments that help slim and sculpt the body -- rose about 26 percent, accounting for more than a third of the company's business.

Shares of the company were up 3 percent to $32.19 on Wednesday morning on the New York Stock Exchange. (Reporting by Mihir Dalal in Bangalore; Editing by Jarshad Kakkrakandy)