In a study by Ruhm and Rossin-Slater, the researchers found that maternity leave was 'a non-event for employers' in terms of absences, morale, and profitability. (Photo: iStock)

If President Trump keeps his promise, the U.S. will join the rest of the industrialized world and provide for some kind of paid maternity leave.

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As explained on the campaign trail, Trump would give new mothers six weeks off with pay — less than the minimum 14 weeks recommended by the United Nations’ International Labor Organization and far less than what professional women get in Western Europe.

Yet as the U.S. moves closer to a national paid leave policy, research suggests that an overly long break isn’t ideal. Parental leave policies that extend to a year or two often set women back professionally, says Ariane Hegewisch, program director for employment and earnings at the Institute for Women’s Policy Research in Washington: “It seems to slow down both women’s career advancement and labor force participation.” 

In Hegewisch’s native Germany, for example, women can take off as much as three years per child with partial pay. Sure enough, 73 percent of German women return to the workforce. But about half of those workers end up working part-time, earning less and advancing more slowly if at all.

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In fact, while the World Economic Forum ranks Germany 13th for gender equality overall, when it comes to women’s economic participation, it’s 57th, behind Mozambique and Belarus. There’s still a generally conservative view of working moms, who are sometimes disparaged as “raven mothers.”

Annette Storr, a public affairs official for UPS in Germany, took a year-and-a-half of leave after her son was born. It was too much, she says: ”I lost contacts on some projects and my network had changed.” Now she’s helping UPS set up an informal mentoring program for women on maternity leave to create “very loose, but regular contact on a voluntary basis,” Storr says. “It’s what I would have wanted for myself.”

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The biggest health benefits for both mother and child manifest in the first six months of leave, says Christopher Ruhm, a professor of public policy and economics at the University of Virginia. Longer breaks wouldn’t work in the U.S., at least not now, he said, noting that Europeans have more job protection, stronger unions and much stronger social insurance.

“We have such different institutions,” he says. ”You’d want to start out cautiously, with a modest leave, then evaluate it.”

Even with legislation, there’s still a cultural barrier. In a survey of more than 25,000 Harvard Business School graduates, women in fields like finance and consulting reported that taking more than six months of leave hurt them professionally. ”Bosses and coworkers draw negative conclusions about women and their commitment,” said Robin Ely, head of the school’s Gender Initiative.

Currently, the federal Family and Medical Leave Act allows employees to take up to 12 weeks of unpaid leave. One initial solution would be to make that paid leave, said University of Virginia’s Ruhm.

That doesn’t even come close to the level at which a women might have to worry about adverse effects on her career, says Maya Rossin-Slater, an assistant professor of economics at the University of California, Santa Barbara.

It’s also modest enough to have limited impact on employers. In a study by Ruhm and Rossin-Slater of 104 small and medium-sized companies in Rhode Island, which offers up to four weeks of paid leave for parents and caregivers, the researchers found that maternity leave was “a non-event for employers” in terms of absences, morale, and profitability.

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