Fwd: Concerns raised over rising birthweights in US

From: Wade T. Smith (wade_smith@harvard.edu)
Date: Wed Jan 02 2002 - 13:48:00 GMT

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    Concerns raised over rising birthweights in US

    By Douglas Belkin, Globe Staff, 1/2/2002

    Fittingly enough, Boston's first baby of 2002 was large.

    Ten days after he was expected, Advaith Prakash - all 8 pounds, 1 ounce
    of him - came into the world at 12:24 a.m. yesterday at St. Elizabeth's
    Medical Center. New mother Sowmia Prakash was in for 20 hours to deliver
    her son, but no matter how hard she pushed, he just wouldn't come out.

    ''He was too big,'' said the proud - and relieved - father, Venkat
    Prakash, a software engineer from the South Shore. ''They had to do a
    caesarean.''

    A few decades ago, Advaith Prekash's size might have been unusual, but
    not these days. The percentage of babies that weigh at least 8 pounds, 8
    ounces increased from 3 percent to 14 percent from 1970 to 1985,
    according to Dr. Dale McGee, a clinical instructor of obstetrics at the
    University of Massachusetts Medical School in Worcester. Fully 15 percent
    of US babies are bigger than Advaith.

    In fact, big children have become so numerous that last year the National
    Center for Health Statistics revised the country's height and weight
    charts for the first time in 23 years to more accurately reflect the
    country's increasingly diverse - and heavier - population.

    Perhaps not surprisingly, more women are having their babies surgically
    delivered because the infants are simply too large to deliver vaginally.
    Caesarean sections like Prekash's now account for a quarter of the births
    in the United States. About a third of them are performed because the
    baby is too large.

    ''We're getting too big,'' complained Tom Samaras, a San Diego author and
    scientist who for years has been railing against what he says will be the
    reason behind our slow self-destruction.

    To be sure, doctors and parents alike are alarmed at the rise of
    childhood obesity, much of it driven by sedentary lifestyles and fatty
    foods. But, in a land of king-size and super-size everything, big babies
    are generally taken as a sign of good health.

    That's especially true when big babies are contrasted with the increase
    in smaller, premature babies that are now routinely saved. Partly as a
    result of these smaller babies, the average birthweight in the United
    States may have plateaued since the mid-1980s, according to Eugene
    DeClercq, a professor of maternal health at the Boston University School
    of Public Health.

    Still all these large babies are prompting a debate unique in the history
    of human development: How big is too big?

    The desire to give birth to big babies is rooted in the notion, based on
    millions of years of evolution, that big babies are stronger, healthier,
    and in possession of better immune system.

    It's a perspective that may need to be reevaluated, Samaras said. ''It's
    a notion that's become outdated and harmful,'' he said. ''We live in a
    paradigm of gluttony. We eat unnaturally. We're getting too big and using
    up too many resources. We need to reevaluate this obsession with size.''

    Larger babies do have health issues. The bigger the baby, the more likely
    the mother is to have a C-section, said Jodi Abbott, maternal fetal
    medicine specialist at Beth Israel Deaconess Medical Center. And, later
    in life, exceptionally large babies may be at a higher risk for obesity
    and myriad obesity-related woes.

    However, Abbott said, bigger babies are partly the outcome of fairly
    positive changes in American culture over the past two generations. Women
    are now encouraged to quit smoking - allowing healthier development of
    the fetus - and they are under less pressure to stay slender while
    pregnant.

    But most anthropologists agree that, over the past 200 years, better
    nutrition is the most significant factor contributing to bigger babies
    and bigger adults.

    Another factor is at work as well: medical technology. A newborn that
    would have been too big, or too small, to survive a century ago can now
    be delivered via caesarean section or kept in an incubator until it is
    healthy enough to thrive on its own.

    ''With regard to evolution, we are in a whole new ballgame,'' said James
    Boster, an anthropologist at the University of Connecticut. ''Through
    most of human history, babies were born in primitive conditions. But lots
    of women died in childbirth. Now, with access to good medical care, the
    previous consequence of having babies that were too big is remedied
    surgically.''

    In the last 200 years, growth has been dramatic.

    In 1760, Norwegian soldiers averaged 5 foot 3. American soldiers drafted
    for World War I averaged 5 foot 7 and 140 pounds. Today, the average
    Californian male is 5 feet 101/2 inches and weighs 188 pounds, Samaras
    said.

    What remains to be seen is how much larger people will grow.

    To project how big humans may become, anthropologists look to the past.
    More than a million years ago our African ancestors stood about 6 feet
    tall, according to Daniel Lieberman, a professor of biological
    anthropology at Harvard University. But as early humans moved from a
    hunter-gatherer society to agriculture, food variety decreased, disease
    increased, and people migrated to colder climates - favoring shorter,
    squatter physiques - and as a result of all these factors, height shrank.

    It is only in the last two centuries that humans have begun to play
    catch-up. They haven't peaked yet but they are getting close, Samaras
    said. In the Netherlands (home to the tallest population in the world),
    the average height of the men is nearly 6 feet 1 inch. It appears
    genetics won't allow humans to get much bigger.

    But the height difference between men and women, which has been shrinking
    for thousands of years, may some day disappear, anthropologists say.

    Thousands of years ago, men were 30 percent taller than women. Between
    30,000 and 5,000 years ago, men and women grew noticably closer in size.
    Today, height differences average 7 percent.

    This gender gap is directly related to mating habits, scientists say. The
    more polygamous a species, the greater the size differential between male
    and female. The gender gap of 30 percent is anthropological proof that
    human ancestors were much more polygamous, said Steve Gaulin, a professor
    of anthropology and psychology at the University of Pittsburgh. And the
    decrease is indicative of the monogamy typically practiced today.

    Social constructs have affected this part of our evolution, Boster says.
    ''There's no way of telling for sure, but were we to be absolutely
    monogamous, then the 7 percent stature difference might disappear,''
    Boster said.

    Back in St. Elizabeth's, Venkat Prakash was thinking less about evolution
    and more about his wife: ''If we have another one, hopefully he won't be
    so big.''

    This story ran on page B1 of the Boston Globe on 1/2/2002. Copyright
    2002 Globe Newspaper Company.

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