Drop in birth defects
The number of fetuses developing two severe types of birth defects each year has fallen about 26 per cent since the United States started adding folic acid to some foods, federal officials reported on Thursday.
But the decrease in prevalence of spina bifida and anencephaly was smaller than what had been expected by researchers, raising doubts that the nation will be able to achieve a 50-per cent reduction in these devastating neural tube defects by 2010.
Spina bifida, a deformation of the spine, is the leading cause of childhood paralysis in the United States. Anencephaly, the congenital absence of much of the brain and spinal cord, results in miscarriage, stillbirth or an infant's death shortly after birth.
The Food and Drug Administration made it mandatory in 1998 for enriched bread, pasta and other cereal grains to be fortified with folic acid, which is also found in leafy green vegetables, some beans and orange juice.
The incidence of neural tube defects has been shown to drop by up to 70 per cent when women take 400 micrograms of folic acid daily before conception and in the first trimester of pregnancy.
There were an estimated 3,020 pregnancies affected by spina bifida and anencephaly annually in 1999-2000, compared with 4,130 annually from 1995 to 1996, according to a study by the Centers for Disease Control and Prevention.
"Women have increased the folic acid that they're getting from their diet, but it's not enough," said Jenny Williams, a nurse epidemiologist in the CDC's national center on birth defects and developmental disabilities and one of the study's authors.
Williams said at least another 1,000 babies could be born without neural tube defects each year if all women of childbearing age consumed 400 micrograms of folic acid each day in addition to a healthy diet.
A fetus's neural tube develops early in the first trimester, before many women are aware that they are pregnant. About half of all pregnancies in the United States are unplanned, according to the CDC.