Do future health problems begin during gestation?

Do future health problems begin during gestation?

Do future health problems begin during gestation?

Health and medicine explained.
Oct. 10 2008 7:06 AM

Womb Raider

Do future health problems begin during gestation?

Crying baby.
Do future health problems begin during gestation?

"The fault," writes Shakespeare in Julius Caesar, "is not in our stars, but in ourselves." According to Harvard Medical School researchers, though, Shakespeare's statement of free will was all wrong—at least with respect to fat toddlers. Recently, a study of 1,044 mother-child pairs found that 3-year-olds born to mothers who gained too much weight during pregnancy had increased odds of becoming overweight. Somehow, it seemed, these women metabolically programmed their kids to get fat. The New York Times Magazine observed, "We may come to view pregnancy not as a ninth-month wait for the big event, but as the crucible of a major health problem."

The notion that children's futures are foretold early in life has strong narrative appeal (consider the stories of Aladdin, the Lion King, and Harry Potter, who were all destined for greatness). Increasingly, however, even reality-based researchers and media say that events in the womb and early infancy are critical developmental opportunities with irreversible consequences when mishandled. These notions form the backbone of modern parental anxiety (heaven forbid, for example, that a mother is unable to exclusively breast-feed her newborn). More worrisome, pinning complex public-health problems, like childhood obesity, on failed gestation has a blame-the-victim undercurrent. Though the supporting research is often weak, this view may encourage inaction: More support for kids, the thinking goes, might not alter the fate set in motion by irresponsible wombs.

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This fall, the British Broadcasting Corp. will air War in the Womb, a documentary tracing the origins of later depression, autism, and other problems to "fetal-maternal conflict" during pregnancy. Last month, a group of scientists from the Yale Child Study Center reported on functional brain MRI scans on women who'd just given birth. Compared with those who delivered vaginally, mothers who consented to Cesarean sections had brains that were less sensitive to recordings of babies' cries, which the researchers ominously claim can harm "infant physiology, development, maternal mood, and mother–infant relationships in general." During the 1990s, schools administrators complained roundly of students with poor attention and an inability to follow directions. They blamed these behaviors on the epidemic of "crack babies" exposed to drugs while in the womb.

Of course, certain prenatal exposures do cause specific medical disorders. Uncontrolled maternal diabetes can occasionally cause fetal heart defects, and maternal vitamin-D deficiency ups a child's chances of getting rickets later in life. The problem, though, is that large-scale problems also wrongly get blamed on the womb—and, by extension, on the woman who houses it. Womb-centric predictions of a child's future—whether rooted in supposed genetic disparities, gestational maternal-fetal conflict, eating habits during pregnancy, or whatever else—always undersell the role of one's later environment.

Take the so-called crack babies. Hundreds of pregnant women were prosecuted for child endangerment, and one program even offered a cash incentive of $200 to crack users who consented to sterilization. Few people argue crack use is harmless, but the uniquely vengeful approach to incarcerating and punishing female crack addicts arose from the conviction that the drug harmed developing brains for good. In 2001, a team of Boston University pediatricians finally reviewed the evidence and concluded that, in fact, there was "no convincing evidence" for a crack baby syndrome—the whole thing was a made-up affair. (In unusually forceful terms, the authors called it a "grotesque myth" that was "irrationally shaped by socialprejudices.") To some extent, the images of poisoned uteruses were simply a convenient cover for bad urban education.

These myths arise from a broader frustration—and lack of rigor—in social-science research. Observe how Steven Levitt and Stephen Dubner try to explain school failure in their otherwise sensible best-seller Freakonomics. Using data from the federal Early Childhood Longitudinal Study, they separate factors that do predict test scores (highly educated parents, high socioeconomic status, a maternal age over 30 years at time of first birth) and others that don't matter (moving to a better neighborhood, attending Head Start, watching less television, and having parents read to children daily). The authors conclude that securing a child's school success "isn't so much a matter of what you do as a parent; it's who you are."

But instead of admitting they can't capture the nuances of good child-rearing, they turn to biology. To explain how socioeconomic disparities affect test scores—apparently, Dubner and Levitt think parents can do little that matters—they trot out the old canard of IQ, the "strongly hereditary" trait they think drives educational and parenting success. Because their logistical regression models identify no practical strategies to help kids, they suggest that the problems must be in the genes. (The Bell Curve, Charles Murray's monumental tome of foolishness from 1994, made the same point: A kid is only as promising as his inherited IQ prophesizes. From the American Enterprise Institute, these days Murray claims 80 percent of Americans are biologically incapable of understanding college-level material.)

That impulse is understandable. It's easier—for parents, doctors, educators—to say an obese toddler has a slow metabolism than to teach the family better eating and exercise habits. Since 1970, childhood obesity rates have quadrupled. If fetal programming mattered a lot, adult obesity increases would lag years behind. But they don't. According to intelligence researcher James Flynn, the average IQ of the first wave of professional Asian-American immigrants was almost 10 points lower than that of white professionals; within one generation, the gap closed, suggesting that genes don't shackle the mind. As Malcolm Gladwell points out: "There should be no great mystery about Asian achievement. It has to do with hard work and dedication to higher education."

Turning to the womb to explain complex social and public-health problems ultimately means people have given up on changing the things that really matter. That's too bad. The truth is that nothing in this world worth having comes easy. And as any hard-working student who made it to college, overweight person who's changed his or her lifestyle, or adult who's worked through depression can tell you, at some point you have to stop blaming your issues on your mother's uterus.