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Vitamin Sharply Reduces Risk of Birth Defects With AM-Birth Defects-Findings

December 23, 1992

BOSTON (AP) _ Researchers have the strongest evidence yet that pregnant women can sharply lower the risk of severe birth defects by eating plenty of fruits and vegetables or taking a daily multivitamin.

The key is getting enough folic acid. A new study found that sufficient amounts of this vitamin early in pregnancy appears to virtually eliminate spina bifida.

Evidence has been mounting for several years. However, the latest research, conducted in Hungary, is the first to show it works in ordinary women who have never had babies with spinal development problems.

The U.S. Public Health Service recommended in September that all women who are capable of becoming pregnant should take 0.4 milligram of folic acid daily, the amount contained in an ordinary multivitamin. No one knows precisely how little folic acid is necessary to prevent birth defects.

That recommendation was based in part on an early look at the Hungarian study published in Thursday’s New England Journal of Medicine.

″It’s an important study, because it examined this for the first time in a randomized, controlled way in a routine population,″ said Dr. Aubrey Milunsky of Boston University Medical School.

In an editorial in the journal, Dr. Irwin H. Rosenberg of the U.S. Department of Agriculture Human Nutrition Center on Aging at Tufts University called the study ″a landmark.″

The study was directed by Drs. Andrew E. Czeizel and Istvan Dudas of the National Institute of Hygiene in Budapest. They enrolled 4,753 women in the study before the women got pregnant. Half took daily multivitamins that contained 0.8 milligram of folic acid, while the rest got only trace elements.

None of the women getting the vitamins had babies with spina bifida or related spinal problems. Six women in the comparison group of 2,052 had babies with these birth defects, about what was expected in the general population of Hungary.

Major birth defects of all kinds were nearly cut in half among the vitamin users. There were 13 major birth defects per 1,000 births among those getting the vitamins, compared with 23 per 1,000 among those who did not.

In the United States, about 2,500 babies are born each year with so-called neural tube defects, largely spina bifida or anencephaly.

Spina bifida occurs when the vertebrae fail to grow closed, leaving part of the spine exposed. Symptoms vary in severity but can include paralysis and incontinence. Babies with anencephaly are born without brains and die soon after.

Folic acid is found naturally in green leafy vegetables and citrus juices. Women who follow U.S. dietary guidelines can get 0.4 milligram of folic acid a day through food alone. However, typically women consume about half that much.

To prevent birth defects, women must take adequate amounts of folic acid during their first month of pregnancy, when the spine is being formed. However, most women do not even know they are pregnant at this point.

For that reason, the federal guidelines recommend that all women in their childbearing years get adequate amounts of folic acid.

An advisory committee to the U.S. Food and Drug Administration proposed last month that folic acid be routinely added to a variety of foods.

″Any other means of obtaining the recommended amount of folic acid would be difficult,″ said Dr. David Erickson, chief of the Birth Defects and Genetic Diseases Branch at the Centers for Disease Control and Prevention in Atlanta. ″The food fortification approach is the cheapest way to get it into essentially all women.″

Until now, the strongest evidence that folic acid prevents birth defects came from a study sponsored by the British Medical Research Council. It found that women who already had a child with spina bifida could reduce their risk of producing a second one with the defect by 70 percent if they took the vitamin.

″The question that remained was: ‘Were they an unusual group?’ This study answers that,″ said Dr. Michael Katz, vice president for research at the March of Dimes. ″If given to the population at large, you reduce the number of neural tube defects. It’s a very important observation.″

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