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Last year, as my wife and I prepared for the arrival of our second child, I began to worry. My wife is a mid-level manager at an advertising agency with offices around the world. She heads a team, and she’s ferociously dedicated to her work—which translated, late in her pregnancy, to a couple of 80-hour weeks and chronic sleep deprivation. When she came home from work at 2 a.m. for the second time in as many weeks, I started to fear that her grueling schedule might affect her health, and that of our unborn son. As a science journalist, I’ve become familiar with a burgeoning area of research called the fetal origins of disease. It examines how what happens to your mother during pregnancy can affect your vulnerability to any number of lifelong disorders, including asthma, heart disease, obesity, diabetes, and schizophrenia and other psychiatric problems. We’ve internalized some of this science already—we know, for example, that excessive drinking while pregnant isn’t good. Less well known are the consequences of things like infection and severe stress. They, too, may leave a legacy.

My wife’s salary keeps the lights on and a roof over our heads, and funds our 3-year-old daughter’s adventures in preschool. What I earn as a freelance journalist, by contrast, more resembles an allowance, so I do the bulk of the child care. I knew that my wife wouldn’t take well to a conversation about her working too much. Any suggestion that she scale back would probably add to the stress I was arguing she should avoid. Not only might it sound like recrimination, but she was in the final stretch of a major project and probably couldn’t (or wouldn’t) change her work situation just then anyway. So what did I do when she came home at two in the morning? I bit my tongue. Today, some 70 percent of mothers work outside the home. For many of them, that means one of two scenarios: the uncertainty and low pay of variable or part-time work, or in the white-collar world, full-throttle commitment and near-constant availability. According to the American Psychological Association, women report more stress than men, from worry over money, work, and the economy, in that order. And each new generation reports more stress than the previous one did. Given the growing body of research on the importance of Mom’s health during pregnancy, I wondered how it was that women seemed to have so little recourse during this period—to work less, to change duties, to merely acknowledge that gestation might be the least bit taxing.

Partly subsidized by my wife, I set out to better understand why this was the case, and what the fetal-origins research really indicated about potential conflicts between pregnancy and the workplace. What solutions had been devised elsewhere, and how well had they worked? One remarkable aspect of this new field of research is how it has upended medical convention. For decades, many scientists viewed the fetus as a “perfect parasite.” Whatever happened to Mom short of death, the thinking went, the fetus would continue developing unperturbed. (As Annie Murphy Paul points out in Origins: How the Nine Months Before Birth Shape the Rest of Our Lives, not long ago women about to give birth were liquored up by their doctors, because the fetus was considered invulnerable to the mother’s drinking. Maternity wards smelled like bars.) Then, in the late 1980s, a British epidemiologist named David Barker found that he could predict which populations would be most vulnerable to heart disease in middle age by looking at rates of infant mortality and low birth weight. Both measures, Barker believed, were partly determined by mothers’ nutrition during pregnancy. At that time, the medical consensus was that your lifestyle—what you ate, whether you smoked, the exercise you did or didn’t do—determined your risk of heart failure. Disease resulted solely from an interaction between genes and personal choice, in essence. Barker’s findings suggested a more complicated reality: conditions in the womb could increase your chances of falling dead from heart failure decades later. Your mom might shake off flu symptoms after a couple of weeks. But if those weeks of misery occur during gestation, they could forever alter the course of your life. When Barker began publishing his findings, skeptics charged that birth weight was a poor indicator of maternal nutrition. Also, they noted, those regions with the highest prevalence of heart disease were the poorest, and bad habits were known to accompany poverty. Maybe those habits, not the prenatal environment, elevated the risk of cardiovascular problems.

So Barker turned to a data set whose variables were easier to control. In 1944, toward the end of World War II, Allied forces liberated half of the Netherlands but were stopped at the Rhine River. The Nazis blockaded the remaining Dutch territory, preventing shipments of food and fuel. Then a bitterly cold winter set in, and the Dutch began to starve. The Dutch Hunger Winter, as it’s sometimes called, provided an ideal laboratory: a previously well-nourished population starved for roughly four months and then, after liberation in May 1945, returned to a life of relative plenty. Barker collaborated with Dutch scientists who were researching this population, and what they found helped change how we think about chronic disease. Children born to mothers who were pregnant during the famine had double the risk of heart disease later in life compared with children whose mothers didn’t starve. They were more prone to asthma and other lung diseases, as well as to obesity. The early months of gestation are an especially sensitive time, and how far along the mothers were in their pregnancy when the starvation began also seemed to matter. Ezra Susser, a Columbia University epidemiologist and psychiatrist who studied the Dutch famine around the same time as Barker, found that children whose mothers went hungry early in pregnancy had double the risk of schizophrenia compared with those whose mothers starved later in pregnancy or didn’t starve at all.

Scientists have since sought to explain how prenatal conditions can incur long-lasting consequences. In the nine months before birth, a fertilized egg multiplies from one cell to trillions. If that process is like building a house, then a sudden scarcity of brick and mortar—a famine—might change the kind of house that gets built. These alterations don’t determine our destiny; they’re one factor among many that affect our vulnerability to disease. And they don’t necessarily qualify as damage; they may in fact represent an attempt by the fetus to adapt to a world of scarcity. (Take height, which tends to increase as nutrition improves and infections decline. A smaller body is, in theory, better suited to a world with less food, where constant battle with pathogens and parasites drains energy.) But adaptations that aid survival in certain circumstances may increase the risk of disease in others. Some of these changes are “epigenetic,” meaning that they affect how our genes get translated into flesh and blood. The early fetal-origins research hinted at the possibility that simple interventions during pregnancy might yield huge payoffs later in life. “The next generation does not have to suffer from heart disease or osteoporosis. These diseases are not mandated by the human genome,” Barker, who died in 2013, once said. “We could prevent them, had we the will to do so.” To some degree, that prophecy has proved true. The observation of spina bifida and certain other problems in children whose mothers survived the Dutch famine contributed to the discovery that folic acid is necessary for proper development of the fetal brain. Pregnant women now take it routinely—a cheap pill prevents devastating conditions. But not all fetal-origins research yields such easy solutions.

Scientists who study prenatal development are increasingly interested in the maternal immune system. In a 2004 study, a group of researchers including Susser and Alan Brown, another Columbia University epidemiologist, analyzed blood samples collected from pregnant women between 1959 and 1966 for evidence of infection. They matched the results to the mental-health outcomes of the women’s now-adult children.

The presence of antibodies to the flu virus during the first half of pregnancy, they found, correlated with triple the risk of schizophrenia. (Animal studies, including on monkeys, have since shown that activating the mother’s immune system as if it were fighting off an infection can alter the fetal development of the brain and other organs.) While many scientists argue that schizophrenia, thought to afflict about 1 percent of people in the United States, must be genetic, this research suggests that with enough planning and foresight, we might be able to reduce its incidence by preventing infections during pregnancy. In the late aughts, Douglas Almond, an economist at Columbia, and a skeptic of fetal-origins research, published a study testing the possibility that infections during pregnancy could have ramifications decades later. In 1918, the Spanish Flu raged around the world. An estimated one-third of American women of childbearing age contracted the virus. When Almond followed up with people whose mothers were pregnant around the time of the pandemic, he found a generation that had been permanently hobbled. They were less educated, earned less, and were poorer overall than trends had predicted. If gestation is like building a house, then a sudden scarcity of brick and mortar—a famine—might change the kind of house that gets built. The asymmetry of what Almond observed was stunning: Your mom might shake off flu symptoms after a couple of weeks. But if those weeks of misery occur during gestation, they could forever alter the course of your life.

In retrospect, perhaps it’s not surprising that famine and major infections can affect fetal development. But scientists think it may be the immune-system response—not the infection itself—that causes harm. And the immune system has other triggers besides infection, Susser told me. One of them is stress. A kind of subspecialty has emerged examining the long-term consequences of acute prenatal stressors—sudden and extreme conditions that hit an entire population but then disappear, allowing for during-and-after comparisons. The associations unearthed in these circumstances should be treated as “clues,” Susser said, “so you can look for the factors that operate in more-ordinary situations.” In June of 1967, Israel and its Arab neighbors fought a war that lasted just six days. In 2008, scientists in New York and Israel released a study of adults whose mothers had been pregnant during the conflict, and reported a more than fourfold increased risk of schizophrenia among women in that group. (Why not men? One possibility is that male fetuses, often observed to be more sensitive than female ones, may have been miscarried.) In California, women with Arabic names saw a reduction in their babies’ birth weight following the September 11 attacks, possibly due to hostility directed their way, or anxiety over reprisal attacks. Research on Arab women in Michigan didn’t confirm this finding, but another study indicated that across the United States that September, there was a greater occurrence of male fetal death among pregnant women generally. Another study has observed a heightened risk of birth complications among children born to mothers who were pregnant during hurricanes along the Gulf Coast. Still others have looked at bereavement—women who lose a close family member during pregnancy. The children from these pregnancies may have a higher rate of mental illness.

Some of the studies are small, and not all of them find that the stressors affect the babies’ health. But that doesn’t disprove causation, Susser notes. How people respond physiologically to war or grief depends on hard-to-measure variables such as upbringing, culture, and social support that may lead to seemingly contradictory findings. Health writers suffer from a version of medical-student syndrome. We read about what can go wrong and then become sure we’re developing those very symptoms. Only in my case, I projected these worries onto my wife. I could see from the slight bags under her eyes that she wasn’t sleeping enough. And I could sense, from her preoccupied demeanor, that even when she was home, she never stopped thinking about work. But I reminded myself that my wife had a well-paying job that, whatever its demands, provided fulfillment. Her situation was very different from living through a war, losing a loved one, or contracting the flu. 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.” It’s when support is lacking and the stressors begin piling on that obvious problems begin to emerge. One possible explanation for the differing outcomes is this: contrasting social realities may affect how citizens of different countries respond to stressors. Denmark and other Nordic countries have legendary social safety nets, including laws that require employers to accommodate pregnant women by changing their duties or, if they can’t, allowing the women to go on leave. The absence of a relationship between maternal stress and preterm birth in Denmark, Danish scientists note, may really show that preventive measures are working, not that job strain never causes problems. Research from France suggests as much. By the 1970s, French scientists had established that job strain and physically demanding work were clearly correlated with an elevated risk of preterm birth. But in later studies, the relationship seemed to have disappeared. What happened?

National policies first implemented in 1972 permitted women to reduce their hours, change duties, or take time off while pregnant. (These days, France also requires women to get prenatal medical care and take prenatal leave—a government-in-your-business approach that can seem jarring to Americans.) Preterm birth is a leading driver of infant mortality in the United States and predicts an increased risk of numerous chronic diseases later in life. So one notable facet of France’s experience is that, as provisions protecting pregnant women in the workplace expanded in the late 20th century, the incidence of preterm birth fell. By 1988, it had declined to 3.8 percent—a 45 percent decrease from the early 1970s, and less than half the U.S. rate today. (It has since inched back up, possibly because of an increasing number of elective C-sections.) Numerous studies, meanwhile, have linked maternal stress and anxiety during pregnancy to preterm birth. One problem with this research, however, is that much of it relies on mothers’ subjective descriptions of stress. Scientists try to circumvent this issue by measuring biological factors, including the stress hormone cortisol and markers of immune function. These studies are somewhat more compelling, although they’re also relatively small and don’t necessarily show causation. One such study, from 2012, led by scientists at the University of Colorado at Denver, linked pregnancy-related stress and inflammation to preterm birth.

Considering the world we evolved in, populated by lions—and other humans—we should be able to handle stress. But even among wild primates that still fend off lions, unremitting social stress quickly erodes health. In baboon troops, the dominant male greatly determines the culture of the group, and observers have noted that when highly aggressive males take over, pregnant females can become so distressed that they spontaneously miscarry. Controlled experiments on primates are even more compelling. In studies at the University of Wisconsin at Madison, scientists exposed pregnant monkeys to intermittent horn blasts once daily for 10 minutes toward the end of their terms—in the grand scheme of things (think lions), a relatively mild stressor. The monkeys born to these mothers grew up more anxious, and had a slightly depressed immune response in youth. Only once my wife was on maternity leave did I ask about her work experience during pregnancy. Had she worried? No, she said. Apparently only I, the nonpregnant one, had fretted. “I know my limits,” she said. How? Years earlier, after weeks of work-related sleep deprivation, she’d been talking with someone when she woke up mid-sentence and realized she’d been speaking gibberish. She vowed never to end up there again. How close had she come this time? If 10 was delirium and talking nonsense, she said, she’d reached a five. And if the dial had turned much further, she would have bowed out.

I found this somewhat reassuring, especially when she explained the techniques she’d developed for managing a job so rife with chaos and uncertainty that whenever she related the day’s insanity over dinner, I became tense. She always created contingency plans, she said. She informed clients of problems when they arose, not at the 11th hour—a way of managing fallout from unmet expectations. And maybe most important, she’d learned to remind herself that, whatever catastrophe seemed to be looming, it wasn’t the end of the world. “I’m not saving lives,” she said. All of this echoed what scientists had told me: how you respond to stress isn’t written in stone; managing it is a skill that can be learned. In California, women with Arabic names saw a reduction in their babies’ birth weight following the September 11 attacks. I still had one lingering anxiety: her sleep deprivation. Experiments on human volunteers suggest that a lack of sleep can induce a derangement of the immune system similar to what’s seen under chronic stress. Michele Okun, a researcher at the University of Colorado at Colorado Springs, has linked sleep deficiency to an increased risk of preterm birth. The fact is, though, success in upper-echelon positions sometimes requires 80-hour weeks, pregnancy be damned. Marissa Mayer, the CEO of Yahoo, launched an ambitious effort to turn around the company while six months pregnant. Sheryl Sandberg, the COO of Facebook, worked through what sounds like severe morning sickness. I’m not suggesting that these women, who have become symbols of female ascendancy, did something wrong.

Here’s why: the science indicates that how we respond to stress depends in large part on how much control we think we have over it. If you’re excited by your job, invigorated by its challenges, made to feel alive by it, it’s probably not going to wear you down. And Mayer and Sandberg have more control than most. Sandberg’s book, Lean In, begins with her “lumbering” while pregnant across the parking lot at Google, where she worked at the time, wondering why no designated spaces existed for expectant mothers, and then promptly fixing that problem. Mayer had a nursery built in her office, and staffed it with a nanny. Indeed, both women had plenty of help—from husbands, assistants, and so on. And my wife has me—providing the child care, cooking dinner, and trying to make sure she eats her vegetables. All of this, which scientists describe as “social support,” can shape our response to stress. It’s when support is lacking and the stressors begin piling on—a lack of job security, anxiety-provoking relationships, falling behind on the rent—that obvious problems begin to emerge. “You put everything in a bucket,” Okun told me, “and eventually the bucket is going to overflow.” One damp evening last November, I squeezed into a small conference room at the University of California at San Francisco, accompanied by perhaps 40 others, many of them medical professionals. We’d come for a discussion titled “The Placenta and the Neighborhood,” in which Paula Braveman, the head of the university’s Center on Social Disparities in Health, would explore new thinking on the persistent discrepancies in health tied to class and race in the United States, and how those discrepancies likely begin before birth.

Though I’d set out to investigate how the pressures on my wife might affect her health, and our child’s, I knew I couldn’t write about stress and pregnancy without looking at the consequences for women near the bottom of the socioeconomic ladder, where a qualitatively different kind of stress prevails. If famine and infection are the first two pillars of the fetal-origins field, poverty is quickly becoming the third. Braveman laid out the argument: Experiences that tend to correlate with class and race—neighborhood violence, social isolation, financial insecurity—induce a state of chronic stress. This response, meant to protect us from acute threats like man-eating bears, ends up wreaking havoc on our bodies over time, altering immune and circulatory function. In pregnancy, these changes may affect the placenta, birth outcomes, and the long-term health of the child. At least, that’s the theory. There’s little doubt that poverty is bad for you. The prevalence of nearly every factor known to erode health—lousy diet, lack of exercise, smoking, and so on—increases as one descends the socioeconomic ladder. But when scientists try to control for these factors—comparing rich smokers with poor smokers, say, or affluent couch potatoes with poor ones—they still find a disparity. The growing suspicion, says Braveman, is that stress is “a missing piece of the puzzle.” This is not the stress of working late to finish a presentation. This is better understood as rage, humiliation, and shame capped with a sense of powerlessness. This type of stress begins shaping vulnerability to disease, Braveman and others think, during pregnancy. Variations in preterm birthrates by class and race provide evidence. Poor whites have an elevated risk of preterm birth compared with more-affluent whites, suggesting that poverty drives the disparity. But there also seems to be something about the experience of being African American that, poverty aside, can affect pregnancy. Middle-class and affluent black women have much higher preterm birthrates than similarly well-to-do white women, and blacks in general are one and a half times as likely as whites to have a child prematurely. Is genetics responsible? It seems not. Black women who immigrate to the United States don’t have the same risk of preterm birth as those who are born here do.

What these findings suggest, Braveman told the mostly non-minority-female audience, is that “there’s something toxic about being a woman of color in the U.S.” One ongoing study of 560 inner-city children whose parents have asthma or allergies highlights the idea that social conditions can influence the health of unborn babies. Scientists began following the children’s mothers, most of whom are black or Latina, during pregnancy, and they’ve found that prenatal stress, from sources including money and neighborhood problems, seemed to predict altered immune function at birth. Asthma, which is prevalent among certain urban minorities, doesn’t usually show up until later in childhood. In this cohort, however, the children whose mothers were most stressed during pregnancy were more likely to wheeze as 1-year-olds. Even this research doesn’t show direct causation: the same genetic traits could, in theory, underlie both the mother’s physiological response to stress and the child’s susceptibility to asthma. But then again, the findings parallel those from the monkeys whose mothers were stressed with horn blasts—their immune function was similarly altered. In a recent Nature essay titled “Don’t Blame the Mothers,” Sarah Richardson, a historian of science and philosophy at Harvard, and others, including leaders in the fetal-origins field, warned that the science too often gets translated into mother-blaming. As the research has gained momentum and edged toward scientific fashionability, accusatory-sounding headlines have begun to appear. “The Nutritional Sins of the Mother,” read a recent one in Science. Another, in the United Kingdom’s Daily Mail, proclaimed, “Babies Can ‘Contract’ Depression in the Womb.”

At its worst, the reporting on fetal-origins science gives mothers a new source of anxiety (or even guilt, if they’re looking back in time). Tommy not only requires plenty of extracurricular activities for his college application; to succeed, he needs to have had an optimal prenatal experience, whatever that is. We should be cautious about prescriptive advice. Research shows that in the right amount, stress may be good for pregnant mothers and their unborn children. Janet DiPietro, a professor at Johns Hopkins University, has found, for example, that moderate stress during pregnancy seems to beneficially accelerate development of the fetal nervous system. Completely eliminating such stimuli may pose its own risks. At its worst, the reporting on fetal-origins science gives mothers a new source of anxiety (or even guilt, if they’re looking back in time). The other problem is that the narrow focus on mother and fetus ignores other interfaces—between Mom and the multiple spheres in which she dwells. “We assume complete agency of the individual in our society,” Janet Rich-Edwards, a Harvard scientist who studies maternal health and who co-authored the Nature essay, told me. “That ignores a lot of the truth about women’s situations.” That’s a primary takeaway of the research on poverty: part of what makes poverty toxic may be the lack of control over what’s happening to you. Fetal-origins science may not yet yield many useful guidelines for individual pregnant women (and their husbands) wondering whether their jobs are too stressful. But research by economists does suggest that public policies can improve infants’ health by helping mothers manage work/family conflicts.

In the late 20th century, many European nations expanded maternal-leave policies incrementally, with a rather striking result: even in relatively wealthy populations, the rates of infant mortality declined. The numbers aren’t huge. On average, providing 10 weeks of leave corresponds with a 1 to 2 percent reduction in infant mortality. But the improvements keep growing as the leave increases. Twenty weeks yields a reduction of 2 to 4 percent. Thirty weeks gives you between 7 and 9 percent. Infant health also improves. No one is certain how a few months away from work can have this effect. Public-health experts have assumed it is due solely to time off after the baby’s birth—women who take maternity leave may breast-feed more, and be more diligent about doctor visits and vaccinations. But the economist Sakiko Tanaka notes that birth weights increased after paid-leave mandates took effect, suggesting that the policies somehow improved prenatal conditions. How? One explanation is that many European women start maternity leave before delivery—in Norway, women begin their paid leave at least three weeks before their due date. Not everyone buys that maternity leave improves infant health. Critics charge that the studies don’t show causality, and economists in Canada have not found the same benefits there as in Europe. Even if the associations hold, the lesson isn’t that all women need to take time off before birth, or that they necessarily should. There’s still a lot we don’t know, including when in pregnancy time off might be most beneficial, or under what circumstances.

Evidence from the U.S. also suggests that simply providing leave—whether or not women use it before their babies are born—could improve birth outcomes, in part by reducing pregnant women’s stress. The 1993 Family and Medical Leave Act allows women up to 12 weeks of unpaid maternity leave without fear of losing their jobs. Only about 60 percent of American workers qualify (the company has to have more than 50 employees in a 75-mile radius, and the employee needs to have worked for at least a year and logged 1,250 hours), and few poor women can afford to go without a paycheck for three months (only 12 percent of women in the private sector get paid leave from their employers). Even so, when Maya Rossin-Slater, an economist at UC Santa Barbara, compared birth outcomes from before and after the law went into effect, she found that the preterm birthrate declined slightly and birth weights went up. As in Europe, fewer children were dying. Since American women tend not to take prenatal maternity leave, Rossin-Slater thinks the improvements at birth were largely because women weren’t stressed out during pregnancy about rushing back to work after delivery—or worried that there might not be a job for them to come back to. They may also have found it easier to take time off for prenatal care, which the law allows. One policy that seems to improve birth outcomes is allowing pregnant women to scale back or temporarily change their duties at work The changes are very slight, and Rossin-Slater observed them only among college-educated and married women, the group most able to take time off. One in seven American women lives in poverty. If this cohort could have a similar reprieve, Rossin-Slater suspects, the U.S. would see greater improvements in infant health.

A version of that experiment has occurred. After the 1978 Pregnancy Discrimination Act was passed, five states—California, Hawaii, New Jersey, New York, and Rhode Island—began offering temporary-disability pay to pregnant women. In a working paper, Jenna Stearns, a doctoral candidate at UC Santa Barbara, looked at how birth outcomes changed as a result. Stearns found that the incidence of low birth weight declined by 3.2 percent, and early births (between 37 and 39 weeks of gestation) fell by 7.2 percent. The effect was greatest among single mothers and African American mothers. Parental-leave policies can be too generous. Studies in Europe have found that at some point after six months, parental leave stops producing measurable benefits, says Rossin-Slater, and overly long leaves may begin to hold women back, or make them more likely to drop out of the workforce altogether. But the U.S. lags so far behind—out of the 185 countries that report to the United Nations’ International Labor Organization, we’re one of only two without a national paid-maternity-leave policy—that we are in a sense ideally situated to make dramatic gains. The other policy that seems to improve birth outcomes is allowing pregnant women to scale back or temporarily change their duties at work. In 1979, Quebec followed the French example and passed a law giving women the right to request a change in job responsibilities. A 2007 study on female workers there found that cumulative job strains and stress correlated with double the risk of preterm birth. But the risk dissipated when women invoked the law and switched to less strenuous positions.

When I asked about doing something similar here, I got strong reactions. “Good God, no!,” one researcher said. “What a setback for the equality of women in the workplace.” Harvard’s Sarah Richardson said that she had concerns about policies focused on the health of the fetus: “Well-intended support can move into coercion.” She pointed to the 1908 Supreme Court case Muller v. Oregon. Curt Muller, who owned a laundry business, was found guilty in a state court of making a female employee work more than 10 hours a day, then Oregon’s workday limit for women. He appealed, but the Supreme Court upheld the conviction (and the $10 fine). As one justice put it, because “healthy mothers are essential to vigorous offspring, the physical wellbeing of woman becomes an object of public interest and care in order to preserve the strength and vigor of the race.” Looking back, many scholars see Muller v. Oregon as establishing the precedent for half a century of laws that limited women’s participation in the workplace, all ostensibly to protect unborn children. With court approval, legislation prevented women from working in restaurants at night, and from working in factories in Ohio. Numerous states limited women’s workdays to 10 hours. Even after the 1964 Civil Rights Act made gender-based discrimination illegal, many companies refused to hire women for certain positions, out of concern for their yet-to-be-conceived children. By 1980, an estimated 100,000 jobs were off-limits. No one seemed to consider that women could make these decisions themselves, or that a mother’s inability to secure her livelihood might be the most toxic exposure of all for the fetus. Because of these restrictions, some women sterilized themselves to stay employed.

These issues continue to arise even today. In December, the Supreme Court heard the case of Young v. United Parcel Service. Peggy Young, a delivery person, was pregnant with her third child in 2006 when her doctor and her midwife both recommended that she not lift more than 20 pounds. When she relayed this medical advice to her superiors, UPS forced her to take unpaid leave. Young sued, charging that UPS had violated the Pregnancy Discrimination Act. The government’s Equal Employment Opportunity Commission recently clarified that, under the law, employers must make “reasonable” accommodations for pregnant women. One legacy of the Muller decision may be a fear of inadvertently opening the door to further discrimination through legislation aimed at helping women. Joan Williams, the head of the Center for WorkLife Law at UC Hastings’s College of the Law, told me that a prominent feminist once confided to her that because she didn’t want anything resembling special treatment written into law, she’d fought against maternity leave. “Inside-the-Beltway feminists killed it,” Williams said. She suspects that as a result, unpaid leave came to American mothers a decade later than it might have, folded into the Family and Medical Leave Act—which applies to everyone, not just to women. The U.S. is one of only two countries without a paid-maternity-leave policy. Williams argues that it’s time to reframe the debate as one about families and the workplace, not just women and work. Research suggests that after a woman has a baby, she’s seen as less reliable and dedicated, and her superiors are more likely to pass her over for promotions. She’ll likely earn less in the course of her career. Over time, though, a fatherhood penalty has also become apparent, albeit only for dads who take paternity leave. For most men, becoming a father increases their earnings. But those who take time off are more likely to be demoted. Their colleagues see them as weak, and they, too, may earn less during their careers. The Center for WorkLife Law runs a hotline for reporting discrimination involving parental leave. Complaints by men have ballooned, from less than 2 percent of all calls in 2000 to a quarter today. This is good news, Williams said—a sign that men are pushing back against old, rusted-in-place expectations: you put in 40 years, never get sick, take very little vacation, then retire. That 1950s ideal doesn’t work well for today’s mothers or fathers—or for anyone, really. The solution, says Williams, isn’t to fit women into an untenable norm, but to change the norm. In the end, our son arrived a week late, large and healthy. He’s grown into a solid, bright-eyed baby who laughs and babbles plenty. Between company maternity leave, disability insurance, and a month and a half at partial pay from the State of California (which implemented the country’s first paid-parental-leave program in 2004), my wife cobbled together roughly three and a half months of semi-paid leave. Her employer granted an additional three months unpaid. All of my fretting over her work was perhaps misplaced. My wife was respected; she had control. She was compensated well enough to fund her own European-length leave. If anything, my wife stood as evidence that more women should be in higher positions, and paid better—to no small degree, having power and money equals health, because it gives you more control over your time. But if there’s one clear takeaway from the research on fetal health and workplace strains, it’s that such control shouldn’t be a luxury afforded only to affluent women. In January, President Obama announced that he would direct federal agencies to allow employees to take six weeks of paid sick leave for the arrival of a child. He also proposed creating a $2.2 billion fund to help states develop their own paid-leave programs for all workers. That proposal seems unlikely to get much traction—which is a shame, because the research suggests that paid leave could not only help parents manage the demands of work and family but also decrease infant mortality and improve infant health, particularly for those at lower socioeconomic levels. Maybe Americans could finally start living as long as Swedes, who have three years on us, or at least Canadians, who outlive us by two and a half.