Prenatal alcohol exposure affects baby's pain regulation

Washington, Jan 28 (ANI): A new study has shown that prenatal alcohol exposure might alter important areas of brain function related to regulating pain responses.

The researchers have found developmental deficits in newborns related to altered levels of a brain chemical called serotonin (5-HT), which leads to subsequent alterations in patterns of neonatal acute pain responses and/or hypothalamic-pituitary-adrenal (HPA) stress reactivity.

The study shows a "blunted response" to an acutely painful event - a heel lance - in alcohol-exposed human newborns, indicating that prenatal alcohol exposure may alter the brain's developing pain regulatory system.

Tim F. Oberlander, a professor in the Division of Developmental Pediatrics at the BC Children's Hospital, the Child and Family Research Institute (CFRI), and the University of British Columbia said that serotonin reuptake inhibitors (SSRIs) and alcohol alter serotonin, which works to blunt or dampen pain pathways.

The research team recruited mothers, who were in their third trimester of pregnancy. Their 28 infants were examined during the first few days of life: 14 who had been heavily exposed to alcohol prenatally, and 14 born to abstainers or light drinkers.

The study had three key findings.

First, in alcohol exposed newborns, physiological responses to the heel lance, such as heart rate and parts of the nervous system that controls heart rate, were blunted or dampened compared to infants with little or no alcohol exposure.

Second, in response to this painful event, the stress hormone cortisol decreased in exposed infants while [remaining] almost unchanged in our control group.

Finally, the researchers looked at behavioural responses. Using very specific measures of facial expressions - a very well-accepted measure of newborn pain behaviour - they found no differences between the two groups.

However, using a measure of behavioural responsiveness called the Brazelton Neonatal Behavioral Assessment Scale, they found that the exposed infants were less aroused.

"While the role of serotonin, the key pain regulatory chemical in prenatally exposed newborns, needs to be studied further, our findings are similar to those we observed in newborns with prenatal SSRI antidepressant exposure - medications that alter the level of serotonin in the developing brain," said Oberlander.

He further said that the findings show that prenatal alcohol exposure changes critical areas of brain function very early in life, in this case specifically, important areas of brain function related to regulating pain responses.

The study will appear in Alcoholism: Clinical and Experimental Research. (ANI)