Determining the Anal Position Index in Portuguese Newborns: Is It a consistent and Reproducible Measurement?

The anatomical position of the anus is a critical parameter in neonatal physical assessment due to its association with functional symptoms like constipation and anatomical anomalies such as anorectal malformations (ARM). The Anal Position Index (API) provides an objective and useful method for assessing anal positioning, though normal values for Portuguese newborns remain undocumented. We aimed to determine normal API values in Portuguese full-term newborns and assess interobserver variability.