In first-time mothers requiring vacuum-assisted delivery, a lateral episiotomy (angled cut) in the tissue between the vaginal and anal opening more than halves the risk of obstetric anal sphincter injury, a severe form of perineal trauma between the vulva and anus. This according to a randomized clinical study led by researchers at Karolinska Institutet and Stockholm's Danderyd Hospital, the results of which are published in The BMJ . Obstetric Anal Sphincter Injury (OASI), which involves the anal sphincter muscles, can lead to anal incontinence with difficulties retaining gas and feces.
It can also cause sexual problems and impair quality of life. This serious form of perineal injury affects around five per cent of all first-time mothers in Sweden who have a vaginal birth. "Women giving birth for the first time and requiring instrumental birth are at the highest risk of sustaining OASI," says Sophia Brismar Wendel, associate professor in obstetrics and gynecology at the Department of Clinical Sciences, Danderyd Hospital, Karolinska Institutet and senior consultant at the Department of Women's Health, Danderyd Hospital.
"Therefore, we wanted to assess if such injury could be prevented in this group with a lateral episiotomy (angled cut in the perineum) when the baby's head is crowning." Participants were recruited to the EVA (Episiotomy in Vacuum Assisted delivery) trial at eight Swedish hospitals between 2017 and 2023. Over 6 100 pregnant women expecting their first child ag.