Mothers Work Inc., the Philadelphia retailer of maternity clothing, yesterday reported a strong sales gain last month that it attributed to the calendar.

But the Bon-Ton Stores Inc., the York, Pa., department store chain, posted a sales decline, and drugstore retailer Rite Aid Corp. missed analysts' expectations. Bon-Ton cited cool weather and fewer customers.

Here are May results for the three companies, the only local retailers that reported yesterday.

Mothers Work

said same-store sales climbed 4.3 percent in May because of one extra Friday and Saturday during the period compared with May 2007. Same-store sales, a key industry gauge, measure sales at outlets open at least a year, eliminating the effect of store openings and closings.

The company's total monthly sales edged up 0.2 percent to $54.2 million as improved same-store sales were mostly offset by a decline in sales from leased departments and licensed relationships.

The company's leased departments within Sears, Roebuck & Co. stores will close before the end of the third quarter.

Mothers Work cautioned that its June same-store sales results would be hurt by the fact there would be one less Friday and Saturday during the period than a year ago.

Mothers Work operated 760 stores, 771 leased-department locations, and 1,531 total retail locations as of May 31.

Bon-Ton Stores

said same-store sales fell 9.9 percent in May on lower traffic levels and cooler weather. Analysts surveyed by Thomson Financial had expected same-store sales to drop 5 percent.

The company said categories with the strongest monthly performance included ladies' spring outerwear, children's and cosmetics.

Bon-Ton runs 280 stores in the United States, including 11 furniture galleries.

Rite Aid,

the Camp Hill, Pa., drugstore chain, said its May same-store sales rose 1.3 percent, missing Wall Street expectations for a 2.1 percent increase.

As of May 31, Rite Aid operated 5,004 stores in 31 states and the District of Columbia.