Painful medical procedures in infancy may have effects that last beyond the procedure itself. Research indicates that early pain can alter how the nervous system responds to pain later, while epigenetic changes—chemical modifications that affect gene activity without changing DNA—may help explain how early experiences influence later development.
For much of the 20th century, doctors believed newborns did not feel pain, and some infants underwent surgery with little or no anesthesia. That view began to change after a 1987 review in The New England Journal of Medicine concluded that newborns experience pain and can have strong stress responses to it.
Studies of premature infants provide evidence linking repeated painful procedures with biological changes. Babies in neonatal intensive care may undergo around 10 procedures a day, including heel pricks, needle sticks and intubation. One Italian study found that very preterm infants exposed to more skin-breaking procedures had greater changes in a serotonin transporter gene between birth and hospital discharge. A follow-up linked those changes to more negative emotionality at three months.
Research from Canada found that children born very prematurely had greater epigenetic changes at age seven than children born at full term. Neonatal pain was associated with changes linked to more behavioral problems, and a later study connected greater procedural pain in newborns with physical differences in the children’s brains at age eight.
Evidence also suggests that painful experiences can affect responses to later procedures in healthy, full-term infants. In studies published in 1995 and 1997, circumcised boys showed more pain-related behavior during vaccinations at four to six months than uncircumcised boys. Infants who had received a topical anesthetic before circumcision reacted less strongly than those who had not. Researchers have not directly established whether epigenetic changes explain this effect.
Older children can also experience lasting distress. A review found that some children develop post-traumatic stress symptoms after surgery, with reported rates of post-traumatic stress disorder ranging from 12 to 31 percent among children undergoing cardiac surgery. Fear of medical procedures in childhood may also influence how people approach health care as adults.
The evidence connecting these effects specifically to epigenetic memory remains preliminary. However, the findings support taking pain in infants and children seriously. Suggested approaches include using anesthesia for circumcision and pain relief for other painful procedures, providing skin-to-skin contact or breastfeeding during needle sticks, avoiding unnecessary procedures, and preparing older children for what to expect. Necessary medical care should not be avoided, but comfort and pain relief may help lessen its impact.
Sources: Psychology Today.