Opioids in Pregnancy Threaten Baby

Infants exposed to maternal opioid use were at a higher risk of adverse outcomes in the short- and long-term, according to data from the Boston Birth Cohort, a prospectively followed sample of mostly urban, low-income, and multiethnic women.

In a group of 8,509 mother-child pairs, infants who had been exposed to opioids or had documented neonatal abstinence syndrome were at a higher risk for preterm birth (odds ratio 1.49, 95% CI 1.19-1.86) and being born within the 10th lowest percentile of birth weight (OR 1.87, 95% CI 1.41- 2.47) compared with unexposed infants, reported Romuladus Azuine, DrPH, MPH, RN, of the federal Health Resources and Services Administration in Rockville, Maryland, and colleagues.

And later on, exposed offspring, including but not limited to those with neonatal abstinence syndrome, were at a higher risk for conduct disorders or emotional disturbance (OR 2.13, 95% CI 1.20-3.77) and having below normal physiological development before the age of 6 (OR 1.80, 95% CI 1.17-2.79) compared with unexposed infants, the team wrote in JAMA Network Open.

These exposed children also had higher rates of attention-deficit hyperactivity disorder versus those unexposed (OR 2.55, 95% CI 1.42-4.57), among a group of infants followed after age 6.

"Taken together, our data suggests that prenatal opioid exposure was associated with higher risk of different yet interrelated adverse perinatal and postnatal physical health and neurodevelopmental outcomes unfolding over the life course," Azuine and colleagues wrote.

Within the past 15 years, the incidence of neonatal abstinence syndrome in the Boston Birth Cohort (which began in 1998) rose "drastically," from 12.1 per 1,000 births in 2003 to 63.1 per 1,000 in 2012, the authors reported. This rate was nearly 10 times that of the general population, which "further underscores the well-noted need for expanded research and programmatic interventions within these populations."

Certain subgroups of women appeared to be more vulnerable to opioid use and the consequences of neonatal abstinence syndrome in this study, which also aligns with previously identified risk factors -- namely, they were more likely to be multiparous, non-Hispanic white, unmarried, and to have less than a college education, Azuine and co-authors reported.

Because the issues faced by women with opioid use disorder are complex, postpartum interventions that address employment, financial security, and safe housing need to be considered in addition to pregnancy care, wrote Susan Brogly, PhD, of Queens University in Kingston, Ontario, in an accompanying editorial.

"The risks of poor pregnancy and child outcomes in cases of maternal opioid exposure are not because of prenatal opioid exposure alone; ongoing difficult social and environmental circumstances have an important role," she explained.

Brogly said these findings support "a trend toward poorer outcomes" with prenatal opioid exposure, but noted that because outcomes like preterm birth precede neonatal abstinence syndrome, these factors may confound the associations revealed in this study.

However, she emphasized the role of the home environment in some of the longer-term outcomes examined in the study, and said that rather than focusing on the mechanism by which these infants are experiencing developmental delays, what is important is how to create comprehensive strategies that reduce them.

"While there may be scientific interest in further delineating the effects of opioids and [neonatal abstinence syndrome] on child health -- and such knowledge may benefit some mothers -- it can perhaps be argued that the more pertinent research concerns interventions to improve health outcomes in this rapidly growing population of children, regardless of the causal mechanism of impairment," Brogly wrote.

For the study, Azuine and his team collected data from mothers at Boston Medical Center who delivered singleton, live, preterm infants (less than 37 weeks' gestation) with low birth weights (less than 2,500 grams), as well as from a group of mothers who gave birth to full-term, normal-weight infants.

To collect demographic information and data on illicit drug use, in-person interviews were conducted after delivery; pregnancy, birth, and neonatal abstinence outcomes were determined through medical records (electronically, starting in 2003).

Overall, 8,509 mothers were enrolled, of which 454 infants (5.3%) were exposed to opioids, including heroin, oxycodone, and methadone.

Exposed versus unexposed mothers were older, with a lower mean body-mass index (5.6 vs 6.3). They also had higher rates of smoking (83.7% vs 15.6%), drinking (16.7% vs 8.2%), or using stimulants like cocaine, ecstasy, or amphetamines from 6 months before pregnancy to delivery (70.7% vs 2.5%), the authors reported.

This polysubstance use, they said, underscores the fact that "opioid addiction is only part of the problem" and that "the root causes and other substance use should be addressed simultaneously."

In addition to the potential confounding from these pregnancy exposures and the single-center nature of the study, the number of participants lost to follow-up is a limitation of the study, the researchers said. Overall, 14.9% of the original 8,509 records examined were incomplete. In addition, the number of opioid exposures may have been misclassified, since heterogeneous criteria were used to define "exposure," including illicit, therapeutic, and unknown opioid exposures.