Neonatal abstinence syndrome (NAS) has quintupled in the past 12 years, with an incidence of 21 732 newborns in 2012, a trend mirrored in England, Canada, and Western Australia, according to a recent review article in the New England Journal of Medicine.
In light of the increase, the article reviews the epidemiology, clinical features, outcomes, prevention strategies, risk identification and management NAS.
“The increase in cases of the neonatal abstinence syndrome corresponds with the reported rise in opioid use during pregnancy, which is attributed to the more liberal use of prescribed opioids for pain control in pregnant women, illicit use of opioids such as oxycodone and heroin, and a dramatic increase in opioid-substitution programs for the treatment of opioid addiction,” wrote Karen McQueen, RN, PhD, and Jodie Murphy-Oikonen, MSW, PhD, of Lakehead University in Thunder Bay, Ontario, Canada. “The pattern of opioid use has also shifted from an inner-city, low-income population to a more socioeconomically and demographically diverse population that includes pregnant women.”
An estimated 55% to 94% of newborns whose mothers used opioids while pregnant experience NAS, also called neonatal drug withdrawal syndrome and neonatal withdrawal. The investigators note that some researchers’ use of these terms to refer to non-opioid substances can cause confusion, particularly since tools for assessing the syndrome were developed only for opioid exposure.
“The inconsistent terminology can lead to challenges in understanding the magnitude and complexity of the syndrome, the presenting signs, and the most effective treatment strategies,” they wrote. The researchers describe true, opioid-related neonatal abstinence syndrome as primarily involving the central and autonomic nervous systems and the gastrointestinal system. When symptoms appear, typically within the first few days after birth with variations in timing, they can include mild tremors and irritability on the milder end up to fever, excessive weight loss, and seizures in more severe cases.
Primary prevention may need to start with initiatives targeting opioid prescribing practices in women of childbearing age with an emphasis on balancing risks and benefits, particularly since serotonin reuptake inhibitors (SSRIs) and benzodiazepines can exacerbate NAS. Once women already have an addiction, it can be difficult but not impossible to treat. Illegal use of opioids often comes with a chaotic lifestyle that complicates women’s ability to seek, receive, or commit to medical and social services. Although the most commonly prescribed treatment for opioid addiction in pregnancy is methadone, buprenorphine may involve less severe neonatal withdrawal, according to emerging evidence.
Management of NAS in infants should prioritize promoting normal growth and development while averting or minimizing negative outcomes, “including discomfort and seizures in the infant and impaired maternal bonding.” Too little data on nonpharmacologic care exists to inform guidelines, but the approach to the care of the mother-infant dyad is at least as important as treatment itself.
“Ideally, care should be multidisciplinary, collaborative, nonjudgmental and based on the identified needs of the infant-mother dyad so that care of the infant does not occur in isolation from the mother,” the investigators write. “Creating a compassionate, safe environment for the mother is important, since many mothers feel stigmatized and guilty regarding substance use and the neonatal abstinence syndrome, which can lead to impaired communication with health care providers.”
Supportive care in a low-stimulation environment should comprise initial infant care, with rest, swaddling, non-nutritive sucking opportunities and adequate nutrition. If pharmacologic treatment is needed, as in the case of 60% to 80% of newborns with the syndrome, its primary goal is “to relieve moderate-to-severe signs such as seizures, fever, and weight loss or dehydration.”
Although oral morphine solution or methadone is generally accepted as first-line pharmacotherapy, with emerging evidence for sublingual buprenorphine, no universally accepted standards exist regarding dosage, weaning protocols, and supplementary medications. Yet, “recent evidence suggests that the use of a standardized protocol for pharmacologic treatment of the neonatal abstinence syndrome may be more important than the choice of drug.” Adjunctive second-line drugs may include phenobarbital or clonidine but, again, without consensus on when and how to introduce polypharmacy.
The researchers concluded with a brief discussion of long-term outcomes, which are more challenging to track and manage, and a call for more research to fill in the many gaps in the prevention and management of NAS.
McQueen, K, and Murphy-Oikonen, J. Neonatal Abstinence Syndrome. N Engl J Med. 2016;375:2468-2479. doi: 10.1056/NEJMra1600879