Are women having VBAC predisposed to sustaining OASIS?

• Research type

  Research Study

• Full title

  Are women having vaginal birth after Caesarean (VBAC) predisposed to sustaining obstetric anal sphincter injuries (OASIS)?

• IRAS ID

  186140

• Contact name

  Ash Monga

• Contact email

  ash.monga@uhs.nhs.uk

• Sponsor organisation

  University Hospital Southampton NHS Foundation Trust

• Duration of Study in the UK

  0 years, 3 months, 0 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.
  Some studies have also shown VBAC (vaginal birth after caesarean) to be associated with an increased risk of OASIS compared with both women who have had previous vaginal births and those that have not. Sustaining an injury at VBAC has been found to be even more likely in women who require forceps to help deliver the baby. The limitation of these studies was that there was no analysis of the women’s baseline characteristics (e.g. age, ethnicity etc.) and circumstances of the first labour (e.g. why the woman had a caesaerean and whether it was planned or unplanned). It would therefore be worthwhile to investigate whether women having VBAC are at increased risk of sustaining OASIS and whether specific baseline characteristics and reason for caesarean delivery at first delivery make sustaining an OASIS at their next delivery more or less likely.

• REC name

  North West - Preston Research Ethics Committee

• REC reference

  15/NW/0782

• Date of REC Opinion

  29 Sep 2015

• REC opinion

  Favourable Opinion