March 10 (Bloomberg) — Today’s bride is saying yes to more than just one dress. Heather Wetzel plans to wear two when she weds next month: a white ball gown for the ceremony and a strapless knee-length number for the reception.

“Who wants to be seen on Facebook in only one dress on their wedding day, anyway?” says Wetzel, 26, who works for a consulting firm in New York that helps associations manage their operations.

Wetzel and other brides are embracing a trend popularized by celebrities like Chelsea Clinton and singer Carrie Underwood, who both made costume changes during recent nuptials. Traditional wedding gowns have grown so large and ornate that more women are ready for a cute, dance-worthy cocktail dress for the party after, said Denise Wash, a marketing vice president for bridal dressmaker Alfred Angelo.

More than 40 percent of weddings occur between May and July, according to theknot.com, a bridal planning website that tracks the $4.2 billion U.S. market for wedding attire. About 15 percent of brides plan to buy more than one gown, and that may rise to as much as 30 percent as more seek variety, according to Carley Roney, editor-in-chief of the New York site. And that means more matrimonial money for everyone from J. Crew Group Inc. to high-end designers like Amsale.

“We saw this come down from the celebrity, affluent part of the industry, and the last several years it has started moving down to the mainstream bridal markets,” said Brian Beitler, chief marketing officer at closely held David’s Bridal Inc. “We expect the trend to accelerate.”

Detachable Skirts

His company, which operates more than 300 stores, has added short white dresses to its Priscilla of Boston locations. The Conshohocken, Pennsylvania-based retailer also has expanded its assortment at David’s Bridal over the past few years, and introduced two-looks-in-one dresses, with detachable skirts, this spring, Beitler said.

Monique Lhuillier, a Los Angeles-based designer who made two wedding dresses for country western star Underwood last year, is creating more short options for her collection, allowing brides more range of motion. Her best-selling reception look, which goes for more than $7,000, is the “Pixie” Chantilly lace corset worn with a floral embroidered organza miniskirt and a hyacinth-colored sash tied at the waist, she said in an e- mail.

Brides typically spend more than $1,000 on their main wedding gown, according to theknot.com. Over the past decade retailers such as J. Crew and AnnTaylor Stores Corp. have entered the market, and last year wedding dresses alone accounted for $1.7 billion in U.S. sales.

Alfred Angelo

Alfred Angelo, whose gowns mostly sell for just under $1,000, debuted its first little white dress line for spring of 2010, priced at $199 to $549. Clients are choosing among nearly a dozen styles for receptions and other events around their marriage, including showers and rehearsal dinners, said Alfred Angelo’s Wash, who’s based in Philadelphia.

“They want to be a bride as long as possible,” she said.

Luxury designer Amsale, whose flagship salon is on New York’s Madison Avenue, introduced its own little white dress collection in 2008 with designs priced at $900 to $1,200, compared with prices for traditional gowns as high as $12,000. Its website currently features 25 such dresses.

J. Crew

New York-based J. Crew, which joined the bridal market in 2004, expanded secondary interpretations a year ago, starting with a little dress covered in white sequins, said Tom Mora, head of wedding design. Now searching on its website for “reception dresses” yields eight styles priced $150 to $1,495, including a Francesca duchesse satin dress with French lace trim on the hem and peplum-style tiered overlay.

A big part of the charm in changing is comfort. Brides like Wetzel are wearing a large gown-of-their-dreams to the ceremony — some with sleeves for church weddings — and moving to shorter, sexier dresses or streamlined long ones that are easier to dance in. Some make a surprise switch after the first twirl with their fathers.

“People are not dancing to Frank Sinatra for the whole reception,” said theknot.com’s Roney. “It’s more Black Eyed Peas, and that is hard to do in a ball gown.