Fashion designers make a pitch for petite sizes

If you're 5 feet 4 inches or under, small boned, and wear a size 2-10, there's good news. Fashion has found you.

The fashion industry is fast realizing that small American women are big business. More and more firms are diving into the petite market, manufacturing dresses and sportswear tailored for small-size women. Until recently these customers have often had to pay for expensive alternations, shop in the teen department, or have their clothes made.

Designers such as Liz Claiborne and Betty Hanson, as well as companies with such well-known labels as Evan-Picone, Jones New York, Villager, and others, are making a pitch to petites.

Some 70 companies in all are involved in this market. And while women have generally become taller, there are still more than 37 million petite women in this country, according to Business Week.

''This customer has been ignored,'' says designer Liz Claiborne, who knows a good thing when she sees it. ''I decided to design a line for petites because I felt that many small women could not buy fashion without major alterations.

''These women want the same fashions as their taller sisters. They need easy, casual clothes for business and formal things, too,'' she says.

Liz Claiborne launched her regular business five years ago after having worked as top designer for Youthguild for 16 years. Today, many retailers see her as ''the working woman's designer.''

The trim, 5 foot 7 inch designer points out that it took her petite company a year to learn to re-proportion garments. ''Now we know much more about it,'' she says. The line runs the gamut from casual skirts and sweaters to jeans and blouses. She even includes trendy items such as knickers.

''Petites look adorable in knickers . . . like pageboys. Especially when the pants are worn with opaque hose and flats,'' says Miss Claiborne, whose personal wardrobe includes one skirt, lots of pants, and a tuxedo for black-tie evenings.

New York designer Betty Hanson, whose labels bear her name, has also added a petite line to her company. Miss Hanson, who was with Anne Klein for 25 years before opening her own firm in 1976, is known for understated, sophisticated sportswear.

''Our petite line developed out of trunk shows. We found that we couldn't fit the small woman,'' says Miss Hanson, whose family business includes both her husband and son.

Betty Hanson, who is a Junoesque 5 foot 7 inches, is a stickler about sizing. ''You can't just alter things for them . . . pockets, lapels . . . it's impossible. I'm really excited about what we've done. A jacket in a size 4, for example, can't be cut down to fit a size 2 petite,'' she says. She explains that sizes 2, 4, 6, and 8 in better petite sportswear are smaller than her 4 in regular sizes.

''We've gone after the small-boned woman . . . more than height. That's the difference between our designer petites and regular petites,'' she points out.

Her clothes may be small but the prices aren't. Silk blouses retail for about

''A lot of my friends are little. They should be pleased with themselves and make the most of their looks. Most small women are very feminine,'' says Miss Hanson.

With the petite market mushrooming, stores are now developing special departments in which to highlight these garments.

Petite World is the name of the area at Filene's in Boston, a unit of Federated Department Stores Inc. The spring fashions being featured include everything from silk dresses, which are fast becoming best sellers, to one-piece knits and separates.

Prices vary, with a linenlike dress by Taurus II tagged at $38, a cotton-blend blouse by Liz Claiborne at $40, and coordinated cotton twill trousers at $40. Evan-Picone separates done in blue cord are priced at $115 for the jacket and $58 for the skirt.

Retail responses have been encouraging. ''With new resources, (and by) offering weekend clothes, daytime things, and after-five fashions, we're running 60 percent ahead of last year,'' says buyer Ann Murgia, who pioneered the area.

In some cases, petite customers have gone on a shopping spree when they've finally found fashions that fit. ''It's not uncommon for one sale to be $400-500 ,'' she says. ''In one of our stores, we had a $1,100 sale.''

As one customer exclaimed, ''It's like Christmas morning!''