BALTIMORE — One sister is 14. The other is 9. The older girl is high-spirited but responsible, a solid student and a devoted helper at home. Her sister loves to read and watch cooking shows, and she recently scored well above average on citywide standardized tests.
There would be nothing remarkable about these two happy, typical girls if it were not for their mother's history. Yvette H., 38, admits that she used cocaine — along with heroin and alcohol — while she was pregnant with each girl. "A drug addict," she now says ruefully, "isn't really concerned about the baby she's carrying."
When the use of crack cocaine became a nationwide epidemic in the 1980s and 1990s, widespread fears emerged that prenatal exposure would produce a generation of severely damaged children. Newspaper headlines included, "Cocaine: A Vicious Assault on a Child," "Crack's Toll Among Babies: A Joyless View" and "Studies: Future Bleak for Crack Babies."
But researchers are systematically following children who were exposed to cocaine before birth, and their findings suggest the encouraging stories of Yvette H.'s daughters are anything but unusual. So far, these scientists say, the long-term effects of such exposure on brain development and behavior appear relatively small.
"Are there differences? Yes," said Barry Lester, a professor of psychiatry at Brown University who directs the Maternal Lifestyle Study, a large federally financed study of children exposed to cocaine.
"Are they reliable and persistent? Yes. Are they big? No."
Cocaine undoubtedly is bad for the fetus. But experts say its effects are less severe than those of alcohol and are comparable to those of tobacco — two legal substances used much more often by pregnant women, despite health warnings.
Surveys by the Health and Human Services Department in 2006 and 2007 found 5.2 percent of pregnant women reported using any illicit drug, compared with 11.6 percent for alcohol and 16.4 percent for tobacco.
"The argument is not that it's OK to use cocaine in pregnancy, any more than it's OK to smoke cigarettes in pregnancy," said Dr. Deborah Frank, a pediatrician at Boston University. "Neither drug is good for anybody."
But cocaine use in pregnancy has been treated as a moral issue, Frank said. Pregnant women who use illegal drugs commonly lose custody of their children. During the 1990s, many were prosecuted and jailed.
Cocaine slows fetal growth, and exposed infants tend to be born smaller than unexposed ones, with smaller heads. But as these children grow, brain and body size catch up.
At a scientific conference in November, Lester presented an analysis of a pool of studies of 14 groups of cocaine-exposed children — 4,419 in all, ranging in age from 4 to 13. The analysis failed to show a statistically significant effect on IQ or language development. In the largest of the studies, IQ scores of exposed children averaged about 4 points lower at age 7 than those of unexposed children.
In tests that measure specific brain functions, evidence suggests cocaine-exposed children are more likely to have difficulty with tasks that require visual attention and executive function — the brain's ability to set priorities and pay selective attention, enabling the child to focus on the task at hand.
Cocaine exposure also may increase the frequency of defiant behavior and poor conduct, according to Lester's analysis. Some evidence indicates boys may be more vulnerable than girls to behavior problems.
But experts say these findings are subtle, making it difficult to generalize. "Just because it is statistically significant doesn't mean it is a huge public health impact," said Dr. Harolyn Belcher, a pediatrician and head of research at the Kennedy Krieger Institute's Family Center in Baltimore.
Michael Lewis, a professor of pediatrics and psychiatry at the Robert Wood Johnson Medical School in New Brunswick, N.J., said that in a doctor's office or a classroom, "you cannot tell" which children were exposed to cocaine before birth.
He said factors such as poor parenting, poverty and stresses like exposure to violence were far more likely to damage a child's intellectual and emotional development. Plus, growing up in a stable household, with parents who do not abuse alcohol or drugs, can do much to ease any harmful effects of prenatal drug exposure.
By Susan Okie
New York Times
Posted: 02/01/2009 12:01:00 AM CST