Genital tract tears in women giving birth on a birth seat: A cohort study with prospectively collected data.

Background: Birth positions may influence the risk of tears in the genital tract during birth. Birth positions are widely studied yet knowledge on genital tract tears following birth on a birth seat is inconclusive.
Aim: The objective of this study was to describe the proportion of genital tract tears in women who gave birth on a birth seat compared to women who did not.
Method: An observational cohort study based on birth information collected prospectively. In total 10 629 live, singleton, non-instrumental births in cephalic presentation were studied.
Results: Fewer women who gave birth on a birth seat experienced an overall intact genital tract compared to women who gave birth in any other position. Women who gave birth on a birth seat were less likely to have an episiotomy performed. Women who gave birth vaginally on a birth seat after a previous caesarean section may have an increased risk for sustaining a sphincter tear.
Discussion: It is important to be aware of the decreased chance of an overall intact genital tract area when giving birth on a birth seat. Furthermore, there is a possibly increased risk of sphincter tear in women having a vaginal birth after caesarean. It is required and of importance to provide pregnant women with evidence-based information on factors associated with genital tract tears including birth positions.
(Copyright © 2018 Australian College of Midwives. Published by Elsevier Ltd. All rights reserved.)