March 18 (UPI) -- Studies designed to assess risks to pregnant women undergoing treatment for opioid addiction may have significant flaws that effectively overstate the impact of drugs like buprenorphine and methadone on child development, a new analysis found.
In a review of existing research published Wednesday by JAMA Network Open, the authors report that medication-based addiction treatment has been associated with lower cognitive development scores in children in several studies -- but suggest studies showing this are missing part of the picture.
While uncontrolled drug use or withdrawal poses significant risk, both to the mother and baby, researchers say that addiction medications have been linked to better growth and lower risk for premature birth. And mothers, in addition to being less at risk for relapse and overdose, tend to have improved engagement in their pregnancies.
But researchers say many studies on addiction treatment are flawed and fail to provide a true picture of the risks, particularly when weighed against those associated with opioid addiction in pregnancy.
"Our findings suggest that the slight decrease in cognitive test scores for young children that have previously been attributed to opioid medications during pregnancy may actually just be due to problems with study design, particularly recruitment," co-author Dr. Leah Nelson, an addiction medicine fellow at the University of New Mexico Hospitals in Albuquerque, told UPI. "Most previous research is based on observational cohorts and the unexposed children were recruited from families that were not really similar to the recruited opioid exposed children."
Nelson and her colleagues found that there are 27 studies assessing the safety of the effects on unborn children of buprenorphine and methadone. Collectively, they report on developmental outcomes with more than 1,000 children.
However, many of the studies failed to recruit participants for control groups -- children who were not exposed to opioids or treatments for opioid abuse in the womb -- that matched well with the study group.
For example, Nelson said, unexposed children in many of the studies were "more likely to be born to mothers who completed high school, had higher socioeconomic status and were much less likely to be exposed to tobacco use during pregnancy" than those exposed to addition treatments -- meaning that there were significant differences between the two groups.
"With the current data, the effects of opioids cannot be separated from the bigger social and environmental picture," she said. Data in the study shows the number of pregnant women with opioid use disorder in the United States has more than quadrupled over the past decade.
Currently, according to Nelson, guidelines from multiple national medical organizations suggest that medications for opioid use disorder, including methadone and buprenorphine, are preferred over no treatment, uncontrolled drug use or drug withdrawal, each of which "poses risks to the fetus as well as increasing the mother's risk of relapse and possible overdose," she said.
Nelson and her colleagues looked at data from 27 studies that enrolled a total of 1,086 children, finding that 485, or roughly 45 percent, had exposure to medication-based addiction treatment. While opioid use disorder treatment was associated with lower cognitive development scores in children enrolled in the studies, the researchers caution that there were other possible factors as well, including pre-natal exposure to tobacco.
"The vast majority of children with pre-natal medication-based addiction treatment exposure do not have poor outcomes and are normally developing," Nelson said.
"The best things to do," she added, is "fund evidence-based addiction prevention efforts, increase access to addiction treatment with medications for opioid use disorder, improve educational and employment opportunities for women with addiction, provide pre-natal care and social services including parenting skills and support, actively promote smoking cessation during pregnancy and provide universal access to comprehensive early intervention services for exposed children to promote school readiness."
A previous version of this story misstated the potential role addiction treatment medications have on developing babies and the lack of accurate research on the communities that mothers with opioid misuse issues come from.