Fetal MRI reveals how opioid use during pregnancy limits brain growth in utero

Fetuses exposed to opioids in utero display multiple areas of decreased prenatal brain development compared to those that have not been exposed. 

It is estimated that between 14-22% of women in the United States fill an opioid prescription during pregnancy, while one infant with opioid exposure is born every 15 minutes. A new paper published in the American Journal of Roentgenology puts a spotlight on how such use during pregnancy can impact brain development based on measurements obtained from fetal MRI exams.[1]

“Children who were exposed to opioids in utero demonstrate lower school achievement and higher rates of behavioral problems in comparison with unexposed children,” corresponding author Usha D. Nagaraj, MD, with the department of radiology and medical imaging at Cincinnati Children's Hospital Medical Center, and colleagues shared, adding that the underlying cause(s) of these differences are not yet well understood. 

To better understand the differences between fetuses exposed to opioids in utero and those who are not, researchers analyzed 65 third trimester fetal MRI exams (28 exposed, 37 unexposed).  

After completing a series of measurements on each exam, experts observed a total of seven brain measurements that were smaller in the opioid-exposed group. They are listed below: 

  1. Cerebral fronto-occipital diameter (93.8±7.4 mm vs 95.0±8.6 mm) 

  1. Bone biparietal diameter (79.0±6.0 vs 80.3±7.1) 

  1. Brain biparietal diameter (72.9±7.7 mm vs 74.1±8.6 mm) 

  1. Corpus callosum length (37.7±4.0 mm vs 39.4±3.7 mm) 

  1. Vermis height (18.2±2.7 mm vs 18.8±2.6 mm) 

  1. Anterior-posterior pons measurement (11.6±1.4 mm vs 12.1±1.4 mm) 

  1. Transverse cerebellar diameter (40.4±5.1 mm vs 41.4±6.0 mm) 

Conversely, researchers noted increased amniotic fluid and larger fronto-occipital indexes in the exposed group. 

To the experts’ knowledge, their study is one of the largest to date to assess brain growth in opioid-exposed fetuses in utero. 

To learn more about the study’s results, click here

Hannah murhphy headshot

In addition to her background in journalism, Hannah also has patient-facing experience in clinical settings, having spent more than 12 years working as a registered rad tech. She joined Innovate Healthcare in 2021 and has since put her unique expertise to use in her editorial role with Health Imaging.

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