Anorectal rings were found in 13.8% of 1,716 consecutive newborn infants. The anorectal ring was detected in four times as many females as males.
Anorectal rings of the grades discovered in this study dilated spontaneously and did not require treatment.
The incidence of constipation, colic, blood in the stool, excessive straining, distention, tear of the anal skin, and crying with defecation was the same in a group of 168 infants with anorectal rings as it was in a group of 160 infants in whom the anorectal ring was absent.
A thick, fibrous anorectal ring which does not dilate spontaneously may cause obstructive symptoms and require treatment. This type of anorectal ring did not occur in this group of 1,716 infants.
