3.3m children worldwide die of birth defects, study says

Nearly 8 million children worldwide are born with serious birth defects each year and 3.3 million die from them, according to the first-ever global estimate of the toll of genetic disorders ranging from heart deformities to spina bifida. Researchers from the March of Dimes said their report released yesterday was evidence of a ''serious, vastly underappreciated and under-funded public health problem."

More than 94 percent of serious birth defects occur in middle- and low-income countries, many of which lack basic programs to curb birth defects, such as improving maternal nutrition. By comparison, the United States has cut deaths from birth defects nearly in half since 1980 through a combination of prevention and treatments, especially surgery.

Cultural practices also increase the rate of genetic disorders, the ''Global Report on Birth Defects" found. Seven of the 10 countries with the highest birth defect rates are Muslim nations with a tradition of intermarriage of blood relatives, accounting for at last 20 percent of deformities there. In addition, the report said that the advancing average age of child-bearing women worldwide increases the risk of conditions such as Down syndrome.

''We really wanted to bring this toll to the attention of governments, international health organizations, and the public and to provide a road map to move forward," said Christopher P. Howson, an epidemiologist at the March of Dimes.

Many numbers in the report are estimates based on limited information, but the authors said their finding that 6 percent of all children have serious birth defects is conservative because they omitted harder-to-tally, nongenetic disorders like fetal alcohol syndrome, in which maternal alcohol consumption can harm the child. Still, lead author Dr. Bernadette Modell of the Royal Free and University College Medical School in London called her work ''a first cut" that will be refined.

Health advocates applauded the March of Dimes' foray into global issues, noting that the group has played a major role in reductions in birth defects in the United States, advocating such measures as folic acid supplements so that pregnant women can reduce the risk of giving birth to a child with spina bifida or other neural tube defects.

''Birth defects have been, up until now, a priority of what they term higher-income countries," said Dr. Paul Fernhoff, an authority on newborn screening at Emory University in Atlanta. ''There's been this perception that birth defects are rare and [poorer countries] don't have the money or the expertise to deal with them." The new report shows ''it is a common health problem that costs them a lot of money."

The report found that five defects -- congenital heart defects, neural tube defects such as spina bifida, blood disorders such as sickle cell disease, Down syndrome, and a blood disease called G6PD deficiency -- account for 26 percent of serious genetic problems. The toll from these defects could be reduced through better prenatal care and early recognition when a fetus is likely to be born with a defect, the authors said.

''Overall mortality and disability from birth defects could be reduced by up to 70 percent if the recommendations in this report were broadly implemented," said coauthor Dr. Arnold Christianson of the National Health Laboratory Service in South Africa.

The report makes no recommendation on ''consanguineous marriage," the custom of men marrying cousins or nieces widely practiced in Muslim countries in the Middle East and Africa.

Scott Allen can be reached at allen@globe.com.