WEDNESDAY, March 20 (HealthDay News) -- If a woman uses methamphetamine during pregnancy, that illegal drug use along with an unstable home environment may lead to an abnormal response to stress in her children, according to the results of a study of 2-year-olds.

Because methamphetamine stimulates the nervous system, prenatal exposure to this drug may affect the development of a child's stress-response system, the researchers explained in the report published in the May issue of the Journal of Studies on Alcohol and Drugs.

Then, if the child is repeatedly exposed to serious stress at an early age -- such as violence in the home -- "the system wears down," said Barry Lester, director of the Brown Center for Children at Risk at Women and Infants Hospital and Brown Medical School in Providence, R.I.

The researchers identified 123 toddlers exposed to methamphetamine in the womb and assessed their reactions when they were briefly separated from their mothers. Normal increases in levels of the stress hormone cortisol did not occur in children who currently had strife in their lives, such as a heavy-drinking mother or one with depression or other mental health problems, they found.

"The lack of hormonal stress response that we observed in these children has serious implications, such as a greater risk for depression, anxiety and attention-deficit/hyperactivity disorder," lead researcher Namik Kirlic, of the University of Tulsa in Oklahoma, said in a journal news release.

However, Lester pointed out that children with a more stable home environment had normal increases in cortisol levels in response to stress.

"It's not the meth alone," said Lester in the news release.

"It's the combination of meth exposure and adversity after birth. We see other things coming into play -- the mother's psychological health, alcohol use, exposure to violence at home or in the community. The postnatal environment is hugely important," Lester explained.

Previous studies have shown that blunted cortisol responses in youngsters are associated with increased risk of developing health and behavioral problems, such as substance abuse, asthma and delinquency.

These new findings suggest that the effects of drug exposure in the womb and stress after birth take hold early in life, Lester said. However, "if you put that child in a good environment, he or she has every chance of developing normally. I think it's important that these children not get labeled," he added.

More information

The March of Dimes has more about the effects of illicit drug use during pregnancy.

SOURCE: Journal of Studies on Alcohol and Drugs, news release, March 20, 2013

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