Related Experiment Video
Updated: May 15, 2025

Assessment and Evaluation of the High Risk Neonate: The NICU Network Neurobehavioral Scale
Published on: August 25, 2014
Antenatal Opioid Exposure and Global and Regional Brain Volumes in Newborns
Yao Wu1, Stephanie L Merhar2,3, Carla M Bann4
1Developing Brain Institute, Children's National Hospital, Washington, DC.
Insights
Antenatal opioid exposure in newborns is linked to smaller brain volumes, including total brain, cortical, and amygdala regions. These findings highlight the developing brain's vulnerability to prenatal opioid exposure.
Area of Science:
- Neuroscience
- Developmental Biology
- Public Health
Background:
- Antenatal opioid exposure is associated with impaired brain growth.
- Previous studies had limitations in sample size and control groups, leaving impacts poorly understood.
Purpose of the Study:
- To compare global, regional, and tissue-specific brain volumes in opioid-exposed newborns versus unexposed controls.
Main Methods:
- The Outcomes of Babies with Opioid Exposure (OBOE) study recruited newborns from 4 US sites.
- 3D volumetric MRI was used to assess brain volumes in opioid-exposed and unexposed newborns before 8 weeks of age.
- Analysis of covariance compared brain volumes, adjusting for key covariates.
Main Results:
- Opioid-exposed newborns had significantly smaller total brain volume (19.55 cm³ less) and reductions in cortical, deep gray matter, white matter, cerebellar, brainstem, and amygdala volumes compared to controls.
- Methadone-exposed newborns showed smaller white matter volume, while buprenorphine-exposed newborns had smaller right amygdala volume.
- Newborns exposed to opioids alone or with other substances showed significant reductions across multiple brain regions.
Conclusions:
- Significant reductions in global and regional brain volumes were observed in antenatally opioid-exposed newborns compared to controls.
- These findings suggest the developing brain is vulnerable to antenatal opioid exposure.
- The effects vary depending on the type and number of substances exposed to during pregnancy.
Importance:
Although antenatal opioid exposure is associated with impaired brain growth, previous studies are limited by small sample sizes and lack of controls. As a result, the impacts of opioid exposure on the developing brain remain poorly understood.
Objective:
To compare global, regional, and tissue-specific brain volumes in opioid-exposed newborns vs unexposed controls.
Design, Setting, And Participants:
In the OBOE (Outcomes of Babies with Opioid Exposure) study, term newborns with antenatal opioid exposure and unexposed controls were recruited at 4 sites in the US from August 2020 to December 2023. Data analysis was performed from August 2020 to December 2024.
Main Outcomes And Measures:
The primary outcome was brain volumes in both groups, assessed via unsedated 3-dimensional (3-D) volumetric magnetic resonance imaging (MRI) in opioid-exposed and unexposed newborns prior to 8 weeks of age. T2-weighted MRI data were acquired on Siemens and Philips 3T scanners and harmonized across sites. Brains were segmented using DrawEM- and 3D U-Net-based pipelines and manual corrections. Brain volumes were compared between groups using analysis of covariance, adjusting for postmenstrual age at MRI, sex, birth weight, maternal smoking, and maternal education.
Results:
A total of 173 newborns with antenatal opioid exposure and 96 unexposed controls were studied. MRIs were performed at a mean (SD) age of 42.84 (2.11) postmenstrual weeks, and 117 newborns (43.5%) were female. The opioid-exposed group had significantly smaller total brain volume (387.51 vs 407.06 cm3; difference, 19.55; 95% CI, 8.75-30.35) and cortical (167.07 vs 176.35 cm3; difference, 9.28; 95% CI, 3.86-14.70), deep gray matter (27.22 vs 28.76 cm3; difference, 1.54; 95% CI, 0.66-2.43), white matter (159.90 vs 166.65 cm3; difference, 6.76; 95% CI, 1.71-11.81), cerebellar (23.47 vs 24.99 cm3; difference, 1.52; 95% CI, 0.67-2.36), brainstem (6.80 vs 7.18 cm3; difference, 0.38; 95% CI, 0.19-0.57), and amygdala volumes (left: 0.48 vs 0.51 cm3; difference, 0.03; 95% CI, 0.004-0.05; right: 0.51 vs 0.55 cm3; difference, 0.04; 95% CI, 0.08-0.07) compared to controls. Methadone-exposed newborns showed significantly smaller white matter volume compared to controls, while buprenorphine-exposed newborns showed significantly smaller right amygdala volume than controls. Compared to controls, newborns exposed to opioids only and those exposed to opioids plus other substances both showed significant reductions in volumes of cortical and deep gray matter, cerebellum, brainstem, right amygdala, and total brain. Polysubstance-exposed newborns additionally showed smaller volumes in white matter and the left amygdala compared to controls.
Conclusions And Relevance:
In a large cohort of antenatally opioid-exposed newborns, there were significant reductions in global and regional brain volumes compared to unexposed controls. These data suggest vulnerability of the developing brain to antenatal opioid exposure, with varying effects depending on the type and number of substances.
Trial Registration:
ClinicalTrials.gov Identifier: NCT04149509.
More Related Videos
05:25Preclinical Model of Prenatal Delta-9-Tetrahydrocannabinol Exposure to Assess Its Impact on Neurodevelopmental Outcomes
Published on: February 28, 2025
15:27Construction of Vapor Chambers Used to Expose Mice to Alcohol During the Equivalent of all Three Trimesters of Human Development
Published on: July 13, 2014