A Danish study found that while most neonatal abstinence syndrome (NAS) cases were linked to maternal opioid use, one-third of treated neonates were not exposed to opioids, and cannabis was the most frequent non-opioid drug involved, with 9% of all NAS cases attributed to cannabis alone.
Neonatologists, perinatal clinicians, pregnant individuals using cannabis
9% of neonatal withdrawal cases linked to cannabis as the only drug (plus tobacco)
What the researchers found
Among 98 neonates pharmacologically treated for NAS in eastern Denmark over 6 years, the incidence remained stable at 0.6 per 1,000 live births. One-third of treated neonates were not exposed to opioids. Cannabis was the most common non-opioid drug causing NAS, with 14% of all treated neonates exposed to cannabis and 9% exposed to cannabis as the only drug besides tobacco.
Why it matters
NAS is typically associated with opioid exposure, but this study found a substantial proportion linked to cannabis. This challenges the common assumption that cannabis withdrawal does not affect newborns and suggests healthcare providers should monitor for NAS after prenatal cannabis exposure.
The numbers in context
447 neonates identified with relevant diagnoses; 98 pharmacologically treated for NAS; incidence: 0.6 per 1,000 live births (stable over 6 years); one-third not exposed to opioids; 14% exposed to cannabis; 9% exposed to cannabis as only drug (plus tobacco)
How the study worked
Historical multicentre cohort study of neonates treated for NAS between 2013 and 2018 in eastern Denmark. The Danish National Patient Register identified 447 neonates with relevant diagnoses; medical record review confirmed 98 were pharmacologically treated for NAS.
What this study cannot tell us
Limited to eastern Denmark, which may not reflect other populations. Relatively small number of cases (98 treated). Tobacco exposure was common and could confound cannabis-specific effects. Retrospective design relies on medical record accuracy.
How to read the evidence
Moderate: multicentre cohort with national registry data and medical record verification, but small case count and retrospective design.
When this study was published
2026 publication analyzing Danish data from 2013-2018.
The bigger picture
While opioid-related NAS has received most attention, this study adds to emerging evidence that other substances, including cannabis, may cause neonatal withdrawal requiring medical treatment. As cannabis use during pregnancy increases, this finding has growing clinical relevance.
Questions still open
- What are the specific symptoms of cannabis-related NAS compared to opioid-related NAS? Do cannabis-related NAS cases require different treatment approaches? Is the mechanism truly withdrawal, or could it be a direct pharmacological effect?
Common questions
Can cannabis cause withdrawal symptoms in newborns?
How common is neonatal abstinence syndrome in Denmark?
Read the original research
The Incidence of Neonatal Abstinence Syndrome Remained Stable in Eastern Denmark From 2013 to 2018 and Was Sometimes Associated With Cannabis.
Acta paediatrica (Oslo, Norway : 1992)
Citation
Vestermark, Vibeke; Kjærbye-Thygesen, Anette; Kesmodel, Ulrik Schiøler. (2026). The Incidence of Neonatal Abstinence Syndrome Remained Stable in Eastern Denmark From 2013 to 2018 and Was Sometimes Associated With Cannabis.. Acta paediatrica (Oslo, Norway : 1992). https://doi.org/10.1111/apa.70443
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