Although the Supreme Court’s decision overturning Roe v. Wade cast a long shadow over reproductive rights, there were some victories to cheer in 2022. Among them was the culmination of a long, hard-fought campaign to sign the Pregnant Workers Fairness Act into law. A win more than a decade in the making, the PWFA mandates that employers grant pregnant workers “reasonable accommodations” — temporary job changes needed to maintain a healthy pregnancy — unless doing so would impose an “undue hardship,” a standard borrowed from the Americans with Disabilities Act. Given that the ADA has been on the books since 1990, employers have decades of experience “accommodating” workers’ medical needs.

­When I tell people about the PWFA’s enactment, most are surprised: Didn’t the law already require employers to assure pregnant workers could keep working safely, they ask? The answer — well, yes and no — reflects decades of disagreement among judges, legislators, and advocates about how to define “equality” when it comes to the distinct medical reality of pregnancy.

From the earliest jurisprudence concerning women and work, capacity for pregnancy has been a basis for disparate treatment. In 1908, the Supreme Court approved an Oregon law capping women’s shifts in certain physically demanding jobs at 10 hours, because “healthy mothers are essential to vigorous offspring,” and thus, “the physical wellbeing of woman becomes an object of public interest and care.” By the time Congress enacted Title VII of the 1964 Civil Rights Act, outlawing discrimination “because of” sex, virtually every state had enacted myriad “protective” laws restricting women’s ability to work on the same terms as men — such as working overtime and holding hazardous jobs.

Although Title VII nullified such laws, employers continued to single out pregnant workers. Especially common were policies excluding them from fringe benefits like health insurance and accrual of seniority during leave. In 1976, the Supreme Court considered such a policy maintained by General Electric, which paid disability benefits to workers absent for medical reasons but paid nothing to people unable to work due to pregnancy. In a challenge brought by workers at a Virginia GE power plant, the justices approved the exclusion. They reasoned that because not all women become pregnant, GE’s decision to disadvantage pregnant workers was not “because of” sex — it was merely “because of” a particular medical condition — and therefore permissible.

Congress swiftly responded by passing the Pregnancy Discrimination Act (PDA) in 1978. In addition to making it explicit that under Title VII, “sex” includes “pregnancy, childbirth, and related medical conditions,” Congress also — in a specific retort to the GE lawsuit — directs that, for “all employment-related purposes” including receipt of fringe benefits, workers affected by pregnancy are to be treated the same as others “similar in their ability or inability to work.” So while the PDA did not mandate that employers must grant any particular benefit to pregnant workers — like paid maternity leave — it says that if an employer does grant such a benefit to others, it must extend the benefit to pregnant workers, too.

The PDA’s effects were seismic. No longer could an employer use pregnancy as a basis for denying an applicant a job, or paying workers less, or firing them. Nor could an employer cite its supposed concern for women’s reproductive health in deciding which jobs they could hold. In 1991, the Supreme Court finally renounced the paternalism of the 1908 decision limiting women’s shifts in certain physically demanding jobs. It did so in a case concerning the so-called “fetal protection” policy adopted by car battery manufacturer Johnson Controls, barring women from holding positions involving contact with lead, known to cause birth defects, unless they could prove sterility. Even though lead also posed danger to men’s reproductive capacity, no such ban was imposed on them.

Women pushed out of the lead-contact jobs — the best-paying in the company — filed suit. The Supreme Court ruled that under the PDA, the company was not entitled to substitute its own judgment for the women workers’: “It is no more appropriate for the courts than it is for the individual employers to decide whether a woman’s reproductive role is more important to herself and her family than her economic role.”

The Johnson Controls ruling may have rejected employers’ efforts to use the potential for pregnancy as a rationale for keeping women out of hazardous or strenuous jobs, but soon, a new conflict arose: Workers whose exceptionally strenuous or dangerous job duties were incompatible with pregnancy itself, and who sought to temporarily avoid those hazards, faced pushback. While employers routinely offered “light duty” to workers recovering from on-the-job injuries, and — as of 1990, when the ADA became law — altered job duties to meet the needs of workers with disabilities, they routinely denied such accommodations to pregnant people. And courts routinely approved such actions under the PDA, concluding that pregnant employees were not “similar” to those favored groups in their “ability or inability to work,” and therefore, not entitled to the same accommodations. Once again, the law treated pregnant workers as the exception, unsuited to the demands of the workplace.

Advocates cheered the Supreme Court’s 2015 decision in Young v. United Parcel Service, Inc., which clarified that employers could only deny pregnant workers needed accommodations if they had a “sufficiently strong” reason for doing so. But in the years after Young, pregnant workers continued to have their job modification requests rejected, and they continued to lose their PDA cases. Indeed, one study found that courts sided with the employer in two-thirds of lawsuits brought by pregnant workers post-Young. The main culprit? Confusion about which workers are sufficiently “similar” to trigger the PDA’s protections.

The PWFA eliminates this comparative hurdle. Employers now must grant reasonable accommodations to pregnant people no matter how they treat “similar” workers, so long as doing so would not impose an “undue hardship.” Nearly 45 years after enacting the PDA, Congress has reaffirmed that the temporary condition of pregnancy is not incompatible with work; it is a normal condition of the modern workplace.