Obstetric anal sphincter injury after episiotomy in vacuum extraction: an epidemiological study using an emulated randomised trial approach.
V AnkarcronaH ZhaoB JacobssonSophia Brismar WendelPublished in: BJOG : an international journal of obstetrics and gynaecology (2021)
To prevent one case of OASIS in first-time mothers delivered with vacuum, 27 episiotomies had to be performed.