Frudinger A, Halligan S, Bartram C I, Spencer J A, Kamm M A
Intestinal Imaging Centre, Department of Obstetrics and Gynaecology, Northwick Park and St. Mark's NHS Hospitals Trust, Harrow, Middlesex, UK.
Br J Obstet Gynaecol. 1999 Mar;106(3):233-7. doi: 10.1111/j.1471-0528.1999.tb08236.x.
To investigate changes in anal canal anatomy following vaginal delivery in women without apparent sphincter injury.
Prospective controlled observational study.
District general hospital.
Consecutive parous and nulliparous women attending a gynaecology outpatient clinic.
All women were examined using anal endosonography, and parous subjects without apparent sphincter injury compared with age-matched nulliparous controls to determine any differences in general anal canal morphology.
Individual anal canal components were measured at defined levels and subjects compared with controls.
Twenty-one of 54 parous women had no anal sphincter scar. Compared with nulliparous women, they had significant anterior sphincter thinning (mean 3.7 mm vs 4.6 mm, P< 0.01) in association with lateral external sphincter thickening (mean 7.0 mm vs 4.4 mm, P<0.01), and longitudinal muscle thickening (mean 2.8 mm vs 2.1 mm, P< 001).
Specific changes in anal morphology have been demonstrated following vaginal delivery in women without apparent sphincter injury.
