title: Determination of the anal position in newborns and in children with chronic constipation: comparative study in two European healthcare centres.
abstract: BACKGROUND
  The objective of this study was to determine the normal anal position index (API) in neonates and in a group of older children with chronic constipation, and to identify the incidence of anterior ectopic anus (AEA) in the two groups.
  
  
  METHODS
  A prospective random study was carried out in two European hospitals determining the API in 1,012 neonates (529 in Group A, and 483 in Group B) and in 64 children suffering chronic constipation of ages between 3 months and 12 years (Group C). The API is defined as the ratio between the fourchette-anal and fourchette-coccygeal distances in girls and the scroto-anal and scroto-coccygeal distances in boys. The gestational age, weight, meconium evacuation and anal calibre were recorded in Groups A and B, and age, sex, and API in Group C. Statistical comparisons were made using Student's t test and Welch's t test for independent sample groups.
  
  
  RESULTS
  The mean API in Group A was 0.53 ± 0.06 in males and 0.40 ± 0.05 in females, and in Group B 0.51 ± 0.06 in males and 0.39 ± 0.08 in females, with significant differences between the sexes (p < 0.0001) in both groups; 1.7% of the neonates in Group A and 2.4% of Group B presented AEA. 4/13 newborns females with AEA presented with severe constipation during their first months of life. For the 64 patients in Group C: 59.3% were female; the mean API was 0.47 ± 0.1 in males and 0.36 ± 0.1 in females (p < 0.0001). The incidence of AEA was 47% in females and 35% in males.
  
  
  CONCLUSIONS
  In the neonates (Groups A and B), the position of the anus in the perineum was more anterior in females than in males (p < 0.0001); 31% of the newborns females with AEA presented with constipation in their first months of life. In the Group C patients, there was a high incidence of AEA, especially in the females, and we consider it to be the probable cause of this defecation disorder.
authors.affiliation: Paediatric Surgery Unit, The Maternal Infant University Hospital, Calle La Violeta s/n, 06010, Badajoz, Spain. raquelillanr@hotmail.com
authors.forename: R
authors.initials: R
authors.lastname: Núñez-Ramos
authors.forename: M A
authors.initials: MA
authors.lastname: Fabbro
authors.forename: M
authors.initials: M
authors.lastname: González-Velasco
authors.forename: R
authors.initials: R
authors.lastname: Núñez Núñez
authors.forename: B
authors.initials: B
authors.lastname: Romanato
authors.forename: L
authors.initials: L
authors.lastname: Vecchiato
authors.forename: S
authors.initials: S
authors.lastname: D'Agostino
authors.forename: E
authors.initials: E
authors.lastname: Blesa Sánchez
mesh_terms: D001003:Anal Canal / Q000002:abnormalities*; D002648:Child; D002675:Child, Preschool; D002908:Chronic Disease; D003248:Constipation / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D007558:Italy / Q000453:epidemiology; D008297:Male; D011446:Prospective Studies; D017678:Sex Distribution; D013030:Spain / Q000453:epidemiology