Background: Heel lancing is a routine procedure for the diagnosis of phenylketonuria in infants. Despite the short- and long-term adverse effects of pain, there are no guidelines for the reduction of such pain. Previous studies evaluated different treatment modalities; however, in most of them, pain response was assessed by subjective measures.

Aims of study: 1. To characterize the pain response of infants by using a computerized analysis of the ECG. 2. To compare six different methods of pain reduction during heel lancing in newborns.

Methods: The time, geometric and frequency domains of the infants' ECG will be computed during heel lancing. 150 healthy full-term infants will be evaluated in six treatment groups: breastfeeding, bottle feeding, skin-to-skin contact, lying on a table without anything, lying with a pacifier and lying while getting a glucose solution. The differences in pain response to these six treatment modalities will be assessed and compared to the infants' length of cry, and scoring of the infants' behavioral response.

Inclusion Criteria:

• normal full-term newborns (>38 weeks)
• Apgar score >=8 at five minutes after delivery.

Exclusion Criteria:

• congenital anomalies
• medical complications
• need for oxygen administration