Helen Robinson took three maternity leaves during her 14-year tenure as a geotechnical field engineer at a Pennsylvania design firm. Returning to work after each leave, she often toiled at remote sites with no shelter for miles, forcing her to pump breast milk in her car. But in communicating to male peers the need to take an unscheduled break to “pump,” Robinson had to make sure they knew it was not related to concrete or site water but nourishment for a new life.

The length Robinson went to feed her babies underscores the difficulties new mothers face on the jobsite. Nursing mothers gained federal protections in 2010, when the Fair Labor Standards Act was amended to require most employers to provide reasonable break times and locations to express milk. Employers with less than 50 workers remain exempt, and none must pay mothers during breaks. But 19 states—13 in the past four years—now have passed laws accommodating pregnant and nursing workers that exceed federal rules. On May 10, the Massachusetts House passed a bill, expected to be approved by the state Senate, that requires employers to provide a “private non-bathroom space” for nursing mothers. The bill mandates “reasonable accommodations” for pregnant workers, such as being assigned less strenuous tasks, but not if they present “undue hardship” on the business.

AGC Massachusetts CEO Robert Petrucelli says construction sites “present a challenge” for compliance because they aren’t “static like a widget manufacturing company.” But he says his members can temporarily relocate pregnant women to the office or provide a trailer for women to pump milk.

Rhode Island implemented a similar law in 2015. Courtney Cannata, a human-resources director at Gilbane Building Co., says the Providence-based construction manager had policies that complied with the law before it was passed but changed its maternity-leave programs last May to allow pregnant women to begin their leaves at 38 weeks, instead of when the child is born, and to take eight weeks off, instead of six. The firm gives another four weeks of paid family leave for a new parent.

The Ironworkers’ union recently unveiled a paid maternity-leave benefit that gives qualified pregnant workers up to six months of coverage, and up to eight weeks postpartum. Union General President Eric Dean says he is open to policies for nursing. “We are walking before we run,” he says.

Kathleen Dobson, safety director at Alberici Constructors, says some employers don’t “even understand” the federal rules and that pregnant women are seen as getting special privileges. “You have your guts ripped out and come back to work in a couple days,” she says. “They had a baby, they get to recover.” Robinson, now a senior project manager at GEI Consultants, says that while protections preventing employees from taking advantage of the new laws are important, awareness brought on by the protections can keep women employees from leaving the industry. “It doesn’t help if we are carving a path, and then nobody is following that path,” she says.