Baby’s Brain Blunted on Meth

Prenatal methamphetamine use stunts stress hormone response

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) There is no doubt that pregnant women should not use meth. If they do, their babies could be at risk for underdeveloped brains and at future risk for mental disorders.

A recent study tested the stress hormones of a group of 2-year-olds that were exposed to methamphetamines in the womb.

The results of the study showed that nearly seven out of 10 kids had abnormally blunted reactions to a stressful situation.

"Don’t use meth, especially when pregnant."

Barry Lester, PhD, director of the Brown Center for the Study of Children at Risk at Brown University’s Warren Alpert Medical School in Rhode Island, and Namik Kirlic, PhD candidate in Psychology at The University of Tulsa in Oklahoma, worked with a team of specialists to investigate how methamphetamine use in the womb and substance abuse and mental disorders in the home during infancy affected stress hormone responses in a group of 2-year-olds.

According to the authors, children that have been exposed to methamphetamines in the womb, or prenatally, are at risk for stunted brain growth and underdevelopment of important connections in the brain, both of which can result in altered brain function and behavior.

In this study, the researchers looked at 123 children, all 2 years of age, and measured exposure to stressors after birth, including parental substance and alcohol abuse, mental disorders and any physical abuse.

The 2-year-olds were then put in a stressful situation, separating them from their caretakers, during a visit to the clinic to judge reactions to stress. Saliva samples were taken to measure the stress hormone cortisol before and after separating the children from their caretakers.

A trained examiner also watched each child while at the clinic to document his or her ability to pay attention, use social skills and regulate their own behavior.

Cortisol levels increased in 32 percent of the kids when they were separated from their caregivers while no increase in cortisol was recorded in the other 68 percent of the kids.

Kids who had been exposed to higher levels of methamphetamines in the womb, and had higher potential for physical abuse by their caregivers at home, were more likely to have increased stress hormones.

No increase in stress hormone – also called a “blunted response” – was more common in kids who had trouble regulating their behavior, poor social skills and caregivers who drank after they were born.

Dr. Lester said "It's not the meth alone [...] 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."

Kids who had higher levels of exposure to methamphetamines in the womb, and who were living with caregivers with a mental disorder, also had a blunted response in stress hormones during separation from their caregivers.

The authors said they believed the study revealed links between prenatal methamphetamine exposure and high levels of stress during infancy and problems with stress hormone function.

“Children exposed to significant postnatal (after delivery) stress showing similar cortisol blunting (non-reacting stress hormone) are at a higher risk for development of depression, post-traumatic stress disorder, attention deficit/hyperactivity disorder, substance use, aggression, and antisocial behaviors, as well as bodily disorders, including autoimmune disorders, fibromyalgia and asthma,” the authors said in reference to a previous study.

The authors concluded that exposure to methamphetamines in the womb could put a child at risk for improper development of the part of the brain that regulates stress hormones, which could cause hyperactivity. However, a long-term stressful environment from caregiver substance abuse and mental disorders or physical abuse was linked to blunted reactivity.

The researchers did not use a comparison group of kids that were not exposed to methamphetamines in the womb. This could be considered a significant limitation.

This study will be published in the May issue of the Journal of Studies on Alcohol and Drugs.

Funding for this project was supported by a grant from the National Institute on Drug Abuse. No conflicts of interest were reported.

Reviewed by: 
Review Date: 
March 19, 2013
Last Updated:
March 20, 2013