Correlation of NICU Withdrawal Assessment Scale with the Finnegan Neonatal Abstinence Scoring Tool in a Cohort of Critically Ill Infants with Opioid Withdrawal

ABSTRACT

Neonatal opioid withdrawal syndrome (NOWS) is a significant public health concern with associated prolonged neonatal hospitalizations. Although the Finnegan Neonatal Abstinence Scoring Tool (FNAST) is validated for use in full-term in-utero opioid-exposed infants, there is no validated tool for preterm opioid-exposed or critically ill infants with iatrogenic opioid withdrawal. We aimed to evaluate the concordance of a novel NICU Withdrawal Assessment Scale (NWAS) designed for this critically ill infant cohort with the traditional FNAST. A total of 15 critically ill infants in the NICU with iatrogenic opioid withdrawal were dual assessed with the NWAS and FNAST. Correlation between the scores was determined using Spearman's correlation and linear regression. The mean gestational age of the cohort was 31.9 weeks (standard deviation [SD] = 6.0) with a range of neonatal diagnoses, and average length of opioid treatment of 35.4 days (SD = 17.9). A total of 93 occurrences of simultaneous NWAS and FNAST scores were obtained. The Spearman's correlation coefficient was Rho = 0.77 (95% confidence interval [CI]: 0.67–0.84, p <0.0001) indicating a strong, positive linear correlation. Linear regression indicated as positive correlation with magnitude of the scores (R = 0.77, y [FNAST score] = 0.85 + 1.49 × [NWAS score], p <0.0001). Further examination of the association with management with the NWAS tool and clinical outcomes can inform future creation of evidence-based guidelines for the treatment of NOWS in premature and critically ill infants.

Key Points

• No validated tool for opioid withdrawal in critically ill infants.

• No validated tool for opioid withdrawal in preterm infants.

• The NWAS is a new tool for preterm and critically ill infants.

• The NWAS is highly correlated with the FNAST.

Keywords

neonatal opioid withdrawal syndrome - preterm infants - newborn intensive care unit - NICU withdrawal assessment scale - validity

Data Availability Statement

The NWAS Tool is copyrighted to Boston Medical Center (2023) and cannot be replicated without permission. The dataset associated with this study is not available for sharing given the waiver of informed consent.

Contributors' Statement

A.H.: data curation, investigation, writing—original draft; R.T.: data curation, investigation, project administration, supervision, writing—review and editing; C.B.: data curation, investigation, project administration, resources, supervision, writing—review and editing; C.S.: conceptualization, data curation, investigation, methodology, project administration, resources, supervision, writing—review and editing; A.F.: data curation, investigation, project administration, writing—review and editing; J.M.: data curation, investigation, methodology, project administration, supervision, writing—review and editing; E.M.W.: conceptualization, data curation, formal analysis, funding acquisition, investigation, methodology, project administration, resources, supervision, writing—original draft, writing—review and editing.

Ethical Approval

The study was approved by the Institutional Review Board of the Boston University Medical Campus and Massachusetts General Hospital with a waiver of informed consent.

Publication History

Received: 09 January 2026

Accepted: 27 January 2026

Accepted Manuscript online:
29 January 2026

Article published online:
10 February 2026

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