Should you bring your unborn baby to work?

The research that looks more directly at work stress and pregnancy is inconsistent, and much of it suffers from methodological problems. Still, the findings troubled me. In 2012, a study of female orthopedic surgeons found that those who worked more than 60 hours a week while pregnant had nearly five times the risk of preterm birth—meaning delivery before 37 weeks of gestation, which can indicate unfavorable conditions in the womb and predict ill health throughout a child’s life—compared with those who worked less. But one glaring problem with this study was that it surveyed women after they gave birth, asking them to remember how much they had worked during pregnancy.

A 2009 study from Ireland that followed 676 pregnant women was better designed. Experiencing two or more work-related stressors—including shift work, temporary work, or working 40 hours or more a week—was associated with a more than fivefold increased risk of preterm birth. A much larger subsequent study from Denmark, however, found no such relationship between “job strain” and preterm birth.

What was I to think? I called up Sylvia Guendelman, a professor of maternal and child health at the University of California at Berkeley. The research could be inconsistent, she said. “But the bulk of evidence seems to suggest that something is there.”