University of Arkansas for Medical Sciences, Arkansas Children's Hospital
UAMS, ACHRI Researcher Affirms Fetal Pain Findings
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 www.iasp-pain.org.
“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.