Adidas is becoming the first major brand to launch a line of workout clothes for pregnant women.

The new line features an array of fitness clothes with details like "no gap" armholes, shorts and capris with padding for extra back support, and drawstrings and expandable waists.

"Pregnant women have an even greater need for well-fitted, comfortable clothes," says Dana Cappiello, designer of Adidas's new line, The Power of Two. "For a woman to spend the majority of her workout tugging and readjusting clothing that does not fit is only an exercise in frustration."

Gap's Old Navy is also launching a maternity line later this month. The clothes, including matte jersey basics, a "wild stripe" dress and dark-rinse boot-cut jeans, will be available only online, at the Old Navy website.

Old Navy is following in Gap's footsteps, which launched an online-only maternity line last year.