ROANOKE TIMES
Copyright (c) 1996, Roanoke Times
DATE: Wednesday, April 10, 1996 TAG: 9604100072
SECTION: NATIONAL/INTERNATIONAL PAGE: A-1 EDITION: METRO
DATELINE: CHICAGO
SOURCE: Associated Press
LARGE WOMEN WHOSE weight is appropriate for their height are not believed to run a higher risk.
Obese mothers are at least twice as likely as thinner women to have babies with debilitating birth defects, two studies found.
And a vitamin known to help prevent such abnormalities appears to offer overweight women no protection, the researchers said.
Both studies, published in today's Journal of the American Medical Association, involved so-called neural tube defects and women who were obese during the child's conception, not those who gained a lot of weight during pregnancy.
The neural-tube defects linked to obesity include spina bifida - an incomplete closure of the spinal column that often results in paralysis - and anencephaly, in which most of the brain is missing. The defects annually afflict some 2,500 U.S. babies.
The researchers who conducted the studies offered no explanation for the apparent link between obesity and birth defects. They speculated that fat women might have some abnormality in their metabolism.
Boston University researchers found that women who weighed 176 to 195 pounds before pregnancy were about twice as likely to have a child with a neural tube defect as women who weighed 110 to 130. The risk was four-fold for women weighing 242 pounds or more.
The study involved 604 infants with a neural tube defect born to women participating in birth-defect research in Boston, Philadelphia and Ontario, Canada.
The researchers did not have information on how tall all the participants were, but believe the increased risk is associated only with obesity, said lead author Martha Werler, an epidemiologist. Large women whose weight is nevertheless appropriate for their height are not believed to run a higher risk.
Werler and colleagues also found that at least 400 micrograms of folic acid a day - the government-recommended dose for women of childbearing age - reduced the risk of neural tube defects by 40 percent in women weighing less than 154 pounds. Folic acid did not reduce the risk in heavier women.
The second study involved 538 babies or fetuses diagnosed with a neural tube defect from 1989 to 1991 in California.
To determine obesity, that study measured mothers' body-mass index - a ratio of height to weight.
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