# Neonatal Abstinence Signs during Treatment: Trajectory, Resurgence and Heterogeneity

## TL;DR

This study explores how withdrawal symptoms in newborns exposed to opioids change over time during treatment, highlighting the need for ongoing monitoring.

## Contribution

The study identifies patterns of symptom resurgence in neonatal abstinence syndrome, suggesting implications for treatment strategies.

## Key findings

- The prevalence of withdrawal signs decreased initially but showed sporadic increases around two weeks of treatment.
- Central nervous system and gastrointestinal signs were notably associated with increased Finnegan scores later in treatment.
- A prolonged treatment duration may be linked to opioid tolerance or withdrawal, requiring further investigation.

## Abstract

Neonatal abstinence syndrome (NAS) presents with a varying severity of withdrawal signs and length of treatment (LOT). We examined the course and relevance of each of the NAS withdrawal signs during treatment in a sample of 182 infants with any prenatal opioid exposure, gestational age ≥ 35 weeks, without other medical conditions, and meeting the criteria for pharmacological treatment. Infants were monitored using the Finnegan Neonatal Abstinence Scoring Tool. Daily mean Finnegan scores were estimated using linear mixed models with random subject effects to account for repeated withdrawal scores from the same subject. Daily item prevalence was estimated using generalized estimating equations with a within-subject exchangeable correlation structure. The median LOT was 12.86 days. The prevalence of withdrawal signs decreased from day one to day three of treatment. However, certain central nervous system (CNS) and gastrointestinal (GI) signs showed sporadic increases in prevalence notable around two weeks of treatment, accounting for increases in Finnegan scores that guided pharmacotherapy. We question whether the resurgence of signs with a prolonged LOT is mainly a consequence of opioid tolerance or withdrawal. Monitoring CNS and GI signs throughout treatment is crucial. Future studies directed to better understand this clinical phenomenon may lead to the refining of NAS pharmacotherapy and perhaps the discovery of treatment alternatives.