Perineal trauma in women having vaginal delivery after previous OASIS
Research type
Research Study
Full title
Perineal trauma in women having vaginal delivery after previous obstetric anal sphincter injury
IRAS ID
185979
Contact name
Ash Monga
Contact email
Sponsor organisation
UHS NHS FT
Duration of Study in the UK
0 years, 4 months, 2 days
Research summary
During childbirth, the vagina stretches to enable the baby to be born. The entrance to the vagina and the perineum – the skin between the vagina and the anus – need to stretch to allow the baby to emerge. When the baby stretches the vagina during birth the skin of the perineum strains, which can lead to a perineal tear. A lot of women will tear to some extent – the majority are superficial and will heal by themselves. Very occasionally a tear can be more serious leading to longer term issues such as leakage of flatus (wind) and faeces (poo). This happens when a tear extends to affect the muscles of the back passage. These are referred to as OASIS (obstetric anal sphincter injuries). These types of injury are the main cause of anal leakage and urgency of passing faeces, and can have a significant effect on quality of life.
There are key risk factors which make sustaining an OASIS more likely, such as, if it’s the woman’s first vaginal birth, her baby weighs more than 4kg, if her labour is induced, if she pushes for a long time when giving birth, if she’s an older mum or if she needed help with instruments (e.g. forceps) to deliver her baby.
There is only very little information available about what happens when women who have sustained an OASIS before go on to have further deliveries. Some studies have shown that these women are at greater risk of having another OASIS than women who have not had an injury before.
It would worthwhile researching this further to see whether we support these findings, but also to establish whether there are clear factors that make sustaining another OASIS more likely and also whether there are factors that make recurrence less likely.REC name
South Central - Hampshire B Research Ethics Committee
REC reference
16/SC/0126
Date of REC Opinion
25 Feb 2016
REC opinion
Favourable Opinion