PHILADELPHIA — Mother’s Work Inc., an upscale retailer of maternity wear, has agreed to acquire The Page Boy Co., a $7 million chain of 22 maternity stores based in Dallas.The deal is expected to close within a month. Terms were not disclosed.

Rebecca Matthias, president and chief operating officer at Mother’s Work, noting Page Boy’s locations in many leading upscale malls, said the acquisition is the “natural next step in our aggressive store expansion program.”

As part of the deal, Mother’s Work will add two vice presidents. Robert E. Pollock, chief operating officer at Page Boy since 1986, will serve in the new position of vice president of real estate. Vana Longwell, formerly president of Wainscott Sportswear in New York, joins Mother’s Work as vice president and general merchandising manager.