Background: Newborn male circumcision causes transient disruptions to infant sleeping, feeding and social behaviors. Circumcision is also associated with increased pain during routine 4 and 6 month vaccination. To date, studies have not assessed the effects of circumcision on pain behavior in the immediate post-operative period. The objective of this study was to determine if circumcision was associated with changes in pain behavior during venipuncture.

Methods: Circumcised neonates (randomly assigned to receive either EMLA or placebo analgesia) and uncircumcised controls were videotaped during venipuncture. The circumcised groups were randomly assigned to venipuncture either 2, 4, 6, 10 or 18 hours after circumcision. Pain was assessed by a blinded research assistant using facial activity and cry duration.

Results: Infant characteristics did not differ (p>0.05) among neonates circumcised with EMLA (n=26) or placebo (n=20) and uncircumcised neonates (n=45). ANOVA revealed no group effects using difference scores(venipucture - baseline) for% facial activity (55% vs. 42% vs. 56%) and% cry duration (50% vs. 41% vs. 47%). However, facial pain scores were correlated with the time of sampling after circumcision (r=0.39, p=0.008).

Conclusion: Circumcised neonates did not differ from uncircumcised neonates in pain behavior following venipuncture. Pain response was affected by the timing of the venipuncture relative to the circumcision. Future studies are necessary to determine the mechanisms that account for the observed results.