UAMS, ACHRI Researcher Affirms Fetal Pain Findings

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‘Pain: Clinical Updates’ Publishes Essay by Anand

LITTLE ROCK – Available scientific evidence on brain development demonstrates that fetuses feel pain as early as the second trimester, says a leading expert in pain research from the University of Arkansas for Medical Sciences (UAMS) and the Arkansas Children’s Hospital Research Institute (ACHRI).

Dr. Kanwaljeet S. Anand, professor of pediatrics, anesthesiology, pharmacology and neurobiology in the UAMS College of Medicine and director of the Pain Neurobiology Laboratory at ACHRI, wrote an essay about ongoing research into fetal pain for the June 2006 issue of Pain: Clinical Updates.

The quarterly publication on issues related to pain management, treatment and research is published by the International Association for the Study of Pain, which has declared 2006 as the Global Year Against Pain in Children.

The article follows research published in the May 2006 issue of the scientific journal Pain by Anand and other researchers that pointed to responses to pain by premature babies suggesting the infants consciously felt pain. In 1987, Anand, who is also the Morris and Hettie Oakley Chair in Critical Care Medicine in the UAMS College of Medicine, proposed his initial theory on neonatal pain.

The essay “Fetal Pain?” is now available online at

“The available scientific evidence makes it possible, even probable, that fetal pain perception occurs well before late gestation,” Anand wrote in his essay summarizing the evidence concerning fetal pain and discussing future research in the field. “Our current understanding of development provides the anatomical structures, the physiological mechanisms and the functional evidence for pain perception developing in the second trimester, certainly not in the first trimester, but well before the third trimester of human gestation.”

Anand said pain perception is not controlled by a hard-wired system that passively transmits pain messages to a certain part of the brain until it is perceived. Rather, he said, the signaling of pain in prenatal development is dependent on the type of stimuli causing the pain, for example intrauterine invasive procedures or fetal surgery.
Pain perception also cannot be assumed to employ the same neural structures in fetuses as in adults, he said. “Clinical and animal research shows that the fetus is not a ‘little adult,’ that the structures used for pain processing in early development are unique and different from those in adults, and that many of these fetal structures and mechanisms are not maintained beyond specific periods of early development,” Anand wrote.

Until now, the prevailing theory was that premature babies react to pain through reflex, but do not actually perceive pain beyond their nerve fibers or spinal cord, and certainly not in the highest sensory center of the brain. Using near infrared spectroscopy, Anand and colleagues studied pain responses in the brains of two-day-old premature babies, correlated with changes in heart rate, blood pressure, and blood oxygen saturations through touch and pain stimuli.

“Pain activates cortical areas in the preterm newborn brain,” the article documenting research by Anand into pain perception in premature babies, was published in the May 2006 issue of Pain, the official journal of the IASP.
UAMS is the state’s only comprehensive academic health center, with five colleges, a graduate school, a medical center, five centers of excellence and a statewide network of regional centers. UAMS has about 2,320 students and 690 medical residents. It is the state’s largest public employer with more than 9,300 employees, including nearly 1,000 physicians who provide medical care to patients at UAMS, Arkansas Children’s Hospital and the VA Medical Center. UAMS and its affiliates have an economic impact in Arkansas of $4.4 billion a year. For more information, visit

Arkansas Children’s Hospital (ACH) is the comprehensive clinical, research and teaching affiliate of the College of Medicine at the University of Arkansas for Medical Sciences. UAMS pediatric faculty physicians and surgeons are on staff at Arkansas Children’s Hospital. Research is a major component of the missions of UAMS and ACH. ACHRI was created to provide a research environment on the ACH campus to meet the research needs of UAMS faculty.