PITTSBURGH, United States — American Eagle Outfitters Inc reported record-high first-quarter comparable sales on Thursday, helped again by strong demand for its Aerie line of lingerie.

The Pittsburgh-based company's comparable sales rose 9 percent in the quarter ended May 5, beating analysts' average estimate of a 5.8 percent increase, according to Thomson Reuters I/B/E/S.

The company forecast earnings per share of 27 to 29 cents for the second quarter, higher than analyst estimates of 25 cents.

American Eagle's Aerie brand of lingerie has become extremely popular in recent years, especially with young adults, and has been successful in taking market share from L Brands' Victoria's Secret.

"After starting a Body Positivity movement, Aerie is nothing short of spectacular, delivering record growth rates and gaining market shares in the intimate space," CEO Jay Schottenstein told investors on a call on Thursday.

The retailer's jeans business and investment in e-commerce also contributed to its success in the quarter, Schottenstein added.

Aerie first-quarter comparable sales gained 38 percent, the retailer's highest growth rate to date.

But seasonal goods such as shorts suffered from a cooler-than-expected spring, the company said.

Net income rose to $39.9 million, or 22 cents per share, in the quarter, from $25.2 million, or 14 cents per share, a year earlier.

Net revenue rose 8 percent to $823 million.

Shares were trading at $22.29 in morning trading after climbing to $22.76 earlier in the session, from $22.61 at Wednesday's close.

By Melissa Fares; editors: Andrea Ricci and Dan Grebler.