And more is ahead: Jujamcyn Theaters plans to add three additional women’s stalls, one men’s stall and three urinals to the St. James, as well as reconfigure that building’s lobby to allow bathroom lines to flow better, as it expands the theater between a run of “Present Laughter” and the much-anticipated stage adaptation of “Frozen.” The Nederlander Organization expects to renovate the Palace Theater, currently home to a revival of “Sunset Boulevard,” as part of a development project that will involve lifting the theater 29 feet and will create more space for bathrooms. And the Shuberts anticipate renovations at three theaters: the Ambassador, the Cort and the Lyceum.

The challenge is clearly visible these days at many shows, including “Waitress,” a hit musical that, with a story about empowerment, a song about pregnancy testing and a joke about estrogen asphyxiation, is drawing a heavily female crowd.

At one evening performance last week, the line for women zigzagged from one side of the mezzanine to the other and back again, contained by ropes, organized by ushers, overflowing into stairwells, hemmed in by a bar. Two ushers controlled the line; a third stood at the bathroom entrance directing women to specific stalls.

“We do this eight times a week,” an usher said. “We have a system.”

As the lights dimmed for Act II to begin, an usher sent six women still waiting in line to the men’s room.

That scene has been playing out throughout the run of the show — at a matinee performance last year, several women sitting in the orchestra section bolted down the aisle as soon as “Bad Idea,” the final song in the first act, began to play; during the intermission, ushers were radioing stage managers to give updates about the line progress.

“This is dangerous — a man almost pushed me down the stairs,” Bonnie Young of Philadelphia said as she slowly moved ahead. Carol Kauffmann, also of Philadelphia, said she was going to dash over to a nearby restaurant and offer them $10 to let her use the bathroom. “It’s my birthday, and my girlfriends brought me to a fancy lunch,” she said. “I have to pee.”

Most Broadway theaters were built in the early 20th century, and featured spaces where men could smoke and women could rest or touch up their makeup, but limited stalls, because women, based on the customs of the times and the complexity of their garments (corsets, anyone?), were less likely to use public toilets, theater owners say.