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Medical News & Perspectives
May 3, 2000

NIDA Seeking Data on Effect of Fetal Exposure to Methamphetamine

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JAMA. 2000;283(17):2225-2226. doi:10.1001/jama.283.17.2225-JMN0503-2-1

Rockville, Md—In recent years, methamphetamine has become a substantial drug of abuse. Along with its increase in popularity comes the likelihood that the drug is being used by pregnant women, with potential damage to the fetus as a result.

Concerned that there may be a "methamphetamine babies" scare looming, similar to the "crack baby" furor of the 1980s, the National Institute on Drug Abuse (NIDA) is looking into what steps it might take to deal with the situation. At the end of March, institute officials called for advice from a group of drug abuse experts who have had research and clinical experience with amphetamines. "We need to get a handle on this fast. Unless we get into this rapidly, we're going to make the same mistake we made with cocaine. I would really like to avoid that," said Alan Leshner, PhD, NIDA's director.

The mistake, he said, was that a lack of scientific information led to erroneous beliefs about the effects of pregnant women's cocaine use on their infants. A decade ago there were widespread predictions that such infants would be born with severe irreversible brain damage. That this proved to be an exaggeration does not minimize later findings that there are, in fact, subtle but significant deficits in mental development among some children exposed to cocaine in utero. Currently, said Leshner, "We're trying to study methamphetamine earlier and more intensively, so we can learn about its effects on the fetus and its mechanism of action."

Researchers are asking, he said, "What do we need to know in order to clarify what's going on and so help us pose what the next array of questions ought to be?" Leshner asked the group. "Even anecdotes might help point us in the right direction." He warned the group not to get "so involved in methodological difficulties that we will not get answers and interventions that are useful." In effect he was asking, What is currently known about the effects of in utero exposure to methamphetamine on brain development? The essential conclusion of a day-long discussion seemed to be: not much.

Numerous users

Leshner pointed out that surveys such as the National Household Survey on Drug Abuse and the Drug Abuse Warning Network report that "large numbers of women have been using methamphetamine," adding, "I think they don't know about the real consequences of using this drug."

In 1996, the Household Survey reported that 4.9 million people have tried methamphetamine at some time. In 1994, the estimate was 3.8 million.

There are places where methamphetamine use is not common, such as Atlanta; Baltimore; Boston; Chicago; Miami; Newark, NJ; New York; New Orleans; Philadelphia; and Washington, DC. On the other hand, methamphetamine use is high in Dallas, Denver, Honolulu, Los Angeles, Minneapolis, Phoenix, St Louis, San Diego, San Francisco, and Seattle, according to one report cited at the NIDA meeting. What is clear is that while methamphetamine was the dominant drug of abuse in the Southwest, it is now spreading to other parts of the West, the South, and the Midwest.

For example, Rizwan Shah, MD, medical director of the Child Abuse Program at Blank Children's Hospital in Des Moines, Iowa, noted a change in adult drug abuse that has been reflected in local infants and children. "The clinic was opened in 1989, during the cocaine abuse era. In 1993, we started seeing methamphetamine-exposed infants in the clinic. Until then, 70% of the infants had been exposed to cocaine; currently, 60% of the infants exposed to drugs have been exposed to methamphetamine. However, the use of methamphetamine goes along with other drugs of abuse, such as marijuana. Polydrug exposure is as common in methamphetamine-exposed infants as it is in cocaine-exposed infants," Shah said.

"Of the drugs that may affect the developing fetus, methamphetamine is one of the least understood both by scientists and the abusers themselves. There's a large and disproportionate number of young women who use this drug, and the problem is potentially enormous," said Jerry Frankenheim, PhD, of NIDA's Division of Neuroscience and Behavioral Research. He outlined two tasks for the group: Summarize what is known scientifically so that a research agenda can be developed, and inform the public about what to expect. Both are necessary, he said, because "there is a perception that methamphetamine is relatively safe."

Prevention or management

In the long run, the plan is to prevent or manage the problem, said Frankenheim in an interview. "Just spreading knowledge will help prevent it. There is no basis for thinking that methamphetamine is safe. We don't know how dangerous it is. But it's certainly not safe."

Methamphetamine is a schedule II drug, a powerfully addictive stimulant with a high potential for abuse. It stimulates the central nervous system, producing increasing alertness, sleeplessness, euphoria, and exhilaration. It has become popular because it is easy to make; it is easy to use—it can be taken with one's morning coffee; and it is cheaper than cocaine, which has come to be regarded by drug abusers as dangerous, said Sheigla B. Murphy, PhD, director of the Institute for Scientific Analysis in San Francisco. Because it metabolizes slowly, a methamphetamine high lasts 8 to 24 hours, whereas with cocaine the effects last only 20 to 30 minutes, she noted.

Murphy reviewed the principal findings from interview studies she has conducted of women who were pregnant or within 6 months of delivery and taking illicit drugs. They used heroin and cocaine as well as methamphetamine, an indication, said Murphy, echoing the point made by Shah and other speakers, that methamphetamine use must be examined within a pattern of polydrug use. The women took methamphetamine because it decreased appetite, helping to control weight, and increased energy—the two principle reasons for using this drug, Murphy said. Of the 226 subjects in the study, only 17% were primary methamphetamine users, but 38% had used it during pregnancy.

Compared with other drug addicts, methamphetamine users were likely to have more uncertainty regarding the effects of the drug on their fetus. "But they were in agreement that it wasn't a good thing to use while pregnant, especially using a drug that causes you not to sleep or to eat," said Murphy.

Neurotoxicity findings

There has not been much evidence of neurotoxicity associated with exposure in utero. However, at the NIDA meeting, Linda Chang, MD, of the Department of Neurology at Harbor–University of California, Los Angeles, Medical Center, Torrance, Calif, presented some new findings.

Using magnetic resonance spectroscopy, Chang and colleagues have found reductions in N-acetyl aspartate in the neurons of children who had been exposed to methamphetamine in utero. The group has also reported a similar reduction of the N-acetyl–containing compounds in adult users of methamphetamine. "The decrease in the adult users may have resulted from neuronal injury or loss, while the decrease in levels in children may indicate lack of neuronal maturity, since N-acetyl aspartate is found only in mature neurons," Chang said.