Episiotomy: What angle do you cut to the midline?

Although episiotomies are the commonest obstetric procedure performed the technique of performing one varies amongst obstetricians and midwives. The angle of episiotomy to the midline in particular has been shown to influence the risk of developing obstetric anal sphincter injuries (OASIS). In order to identify the differences in technique and to identify targets for training we undertook a practice survey of episiotomies to analyse the differences in technique between grades of obstetricians and midwives.

A prospective practice survey of staff working on delivery suite in a tertiary referral unit with 9000 deliveries/year was conducted between 01/10/2014 to 01/03/2015. Each participant was provided with a pictoral representation of a perineum and a pair of standard episiotomy scissors and asked to perform an episiotomy as per their usual practice. The profession and grade of each participant was recorded along with information regarding the incision including the angle to the midline, length of incision and lateral starting distance from the midline. One way ANOVA (unrelated) was used to perform statistical analysis using IBM SPSS v23.

101 staff members participated in the practice survey including 63 midwives, 9 junior trainees, 15 senior trainees and 14 consultants. The mean angle of incision to the midline of episiotomies was 47°, 51°, 66° and 77° for midwives, junior trainees, senior trainees and consultants respectively. The mean angle of incision performed by midwives was significantly different to senior trainees (p>0.01) and consultants (p<0.01). 45% of all episiotomies undertaken by midwives were done at an angle <45° to the midline, compared to 7% by senior trainees and none by consultants.

This study identified clear deficiencies in the performance of episiotomies amongst obstetric trainees and midwives. Both midwives and obstetric trainees need to improve their technique if episiotomies are going to influence the incidence of OASIS and, more importantly the development of faecal incontinence. These results should be used to inform future training programmes to reduce the risks of OASIS.