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February 28, 1997

Study shows that infants feel and remember circumcision pain

TORONTO - A study led by Hospital for Sick Children (SickKids) researchers has demonstrated that not only do male infants feel pain during circumcision, they remember that pain six months later when they receive their routine vaccination. The results of the study, led by Anna Taddio, a graduate student supervised by Dr. Gideon Koren, head of Clinical Pharmacology & Toxicology at SickKids and a Professor of Paediatrics, Pharmacology, and Medicine at the University of Toronto, are reported in the March 1 issue of the British medical journal Lancet.

Earlier research led by this research team had indicated that male infants demonstrate a greater pain response to vaccination than female infants. The current study sought to determine whether there was a difference between circumcised and uncircumcised male infants in their pain response to vaccination, and whether pretreatment of circumcision pain with a topical anaesthetic affected the pain response to vaccination.

The study involved 87 male infants in three groups: 32 uncircumcised infants; 29 infants receiving a topical anaesthetic prior to circumcision; and 26 who were circumcised without pain relief. The infants were recruited to the study through Women's College Hospital. Between ages four and six months, the infants received routine vaccinations from their primary care physician and their pain response to the vaccination was measured.

"What we discovered was that the infants who were uncircumcised demonstrated the least pain during vaccination," Dr. Koren explains. Pain response was measured by monitoring the infants behaviour, inclucing facial expression and duration of crying.

"The infants who were circumcised without a pain reliever showed substantially more pain. The infants who received the topical anaesthetic scored between the other two groups of infants. "

"This study demonstrates two important findings," says Ms. Taddio. "It shows that infants do in fact feel pain, and that a pain experience in the newborn period can affect pain behaviours later on. Adequate pain relief may prevent these changes. Therefore, every measure should be taken to prevent pain in circumcision and other medical and surgical procedures."

Other research team members include Dr. Joel Katz, a pain researcher at The Toronto Hospital, and Lane Ilersich, a graduate student in the Department of Health Administration at U of T.

For more information, please contact:

Public Affairs
The Hospital for Sick Children
555 University Avenue
Suite 1742, Public Affairs, First floor Atrium
Toronto, ON
M5G 1X8
Canada
Phone: 416-813-5058
Fax: 416-813-5328