European Journal of Obstetrics & Gynecology and Reproductive Biology 174 (2014) 46–50

Mediolateral episiotomy: are trained midwives and doctorsapproaching it from a different angle?

Ka Woon Wong, Karthigan Ravindran, James M. Thomas, Vasanth Andrews *

Obstetrics and Gynaecology, Ashford & St Peters’ Hospitals, NHS Foundation Trust, Guildford Road, Chertsey KT16 0PZ, United Kingdom

A R T I C L E I N F O

Article history:

Received 22 September 2013

Received in revised form 4 November 2013

Accepted 2 December 2013

Keywords:

Episiotomy

Angle

Training

Midwives

OASIS

A B S T R A C T

Objectives: The angle at which a mediolateral episiotomy is incised is critical to the risk of obstetric anal

sphincter injuries (OASIS). When a mediolateral episiotomy is incised at least 60 degrees from the

midline it is protective to the anal sphincter. The objective of our study was to investigate how

accoucheurs described and depicted a mediolateral episiotomy.

Study design: One hundred doctors and midwives were invited to complete an interview-administered

questionnaire in a district general hospital in the United Kingdom over a 10-month period commencing

in August 2012. Accoucheurs were asked to describe the angle at which they would cut a mediolateral

episiotomy, and to depict this on a pictorial representation of the perineum. The angle drawn was

calculated by an investigator blinded to the participant’s initial description of a mediolateral episiotomy.

Results: Sixty-one midwives and 39 doctors participated. Doctors and midwives stated they would

perform a mediolateral episiotomy at an angle of 45 degrees from the midline, but midwives depicted

episiotomies 8 degrees closer to the midline (37.3 degrees vs. 44.9 degrees, p = 0.013) than they

described. Seventy-six percent of accoucheurs had undergone formal training in how to perform a

mediolateral episiotomy, but this had no impact on their clinical practice. Accoucheurs who had been

supervised for ten episiotomies before independent practice performed them in keeping with the angle

they described.

Conclusions: Doctors and midwives are unaware of the appropriate angle (60 degrees) at which a

mediolateral episiotomy should be incised at to minimise obstetric anal sphincter injury. The correct

angle should be emphasised to accoucheurs to minimise the risk of anal sphincter damage. In addition

midwives depict episiotomies that are significantly more acute than they describe. Accoucheurs should

also perform at least 10 episiotomies under supervision prior to independent practice. Training

programmes should be devised and validated to improve visual measurement of the episiotomy incision

angle at crowning. Consideration should also be given to the development of novel surgical devices that

help the accoucheur to perform a mediolateral episiotomy accurately.

Crown Copyright � 2013 Published by Elsevier Ireland Ltd. All rights reserved.

Contents lists available at ScienceDirect

European Journal of Obstetrics & Gynecology andReproductive Biology

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1. Introduction

Episiotomy is the most commonly performed obstetric proce-dure that requires suturing [1], but its indications and efficacy aresubject to doubt and its practice has remained controversial.Episiotomies were first described in 1741 and were believed toprevent severe perineal tears, urinary incontinence, anal inconti-nence and pelvic floor relaxation, and to protect the newborn fromintracranial haemorrhage and intrapartum asphyxia [2]. Episio-tomies are usually performed as midline or mediolateral. Theadvantages of midline episiotomies are easier surgical repair,better healing, less postoperative pain and blood loss [3]. They are,however, associated with a significantly higher rate of anal

* Corresponding author. Tel.: +44 7932 714 638; fax: +44 1483472064.

E-mail address: Vasanth_andrews@hotmail.com (V. Andrews).

0301-2115/$ – see front matter . Crown Copyright � 2013 Published by Elsevier Irelan

http://dx.doi.org/10.1016/j.ejogrb.2013.12.002

sphincter damage and therefore when performed in the UnitedKingdom are usually done as a mediolateral episiotomy (MLE) [4–9].

Tincello [10] reviewed midwifery and obstetric textbooks incommon use and found that they recommend an angle of between40 and 60 degrees from the midline for performing a MLE, withoutproviding any evidence for this practice.

It is now apparent that the angle at which an MLE is performedis critical. Andrews et al. found that performing an MLE was anindependent risk factor for obstetric anal sphincter injuries (OASIS)[11], but they calculated the angle after an episiotomy was suturedwas between 20 and 27 degrees [12], which is known to equate toan incision angle of about 40 degrees from the midline [13]. Morerecently, evidence has come to light that when one performs a MLEat least 60 degrees from the midline that it may in fact protectagainst OASIS [13]. In addition Stedenfeldt et al. [14] demonstratedthat there is a U-shaped association between the post-delivery

d Ltd. All rights reserved.

Fig. 1. Pictorial representation of the perineum.

Table 1Numbers of episiotomies performed before independent practice.

Numbers of episiotomies performed

before independent practice

Number of accoucheurs

(total = 100)

0–5 69

5–10 7

>10 24

K.W. Wong et al. / European Journal of Obstetrics & Gynecology and Reproductive Biology 174 (2014) 46–50 47

episiotomy angle and risk of OASIS, and those resulting in an anglebetween 30 and 60 degrees in the so-called ‘‘safe zone’’ minimisethe risk of OASIS. Also when an MLE is performed appropriatelywith an operative vaginal delivery it may actually reduce the risk ofanal sphincter involvement six fold [15].

Nearly 20 years ago Sultan et al. [16] evaluated junior doctorsand midwives views on their training in perineal anatomy andrepair, and reported widespread dissatisfaction with their training.Subsequent to this, simulation based workshops have beenintroduced to train doctors and midwives in perineal anatomyand episiotomy repair techniques [17,18].

With the introduction of almost universal training in episioto-my repair for midwives and doctors, and with the knowledge of theangle at which a MLE should be performed in order to prevent analsphincter damage, we wished to determine the angle at whichaccoucheurs thought an episiotomy should be performed. Inaddition, in order to correlate their theoretical knowledge withtheir practical understanding we ask them to depict the angle theydescribed on a picture of the perineum.

2. Methods

One hundred doctors and midwives were invited by KR and KWto complete an interview-administered questionnaire investigat-ing the indications, concerns and anatomical considerations ofperforming a mediolateral episiotomy. This study was conductedover a 10 month period commencing in August 2012. The studywas undertaken in a district general hospital in the South East ofEngland. Participants were asked to describe the angle at whichthey would cut an episiotomy, and to depict this on a pictorialrepresentation of the perineum (Fig. 1). The angle of theepisiotomy drawn on the pictorial questionnaire was thencalculated by a method previously described [19]. This was doneby an investigator who was blinded to the participant’s descriptionof how they would perform an episiotomy. In addition data wereobtained about whether they had attended any formal training inepisiotomies, and their level of supervision prior to independentpractice in performing an MLE (Fig. 2).

2.1. Statistical analysis

Data were entered onto a Microsoft1 excel database andanalysed with IBM SPSS version 19. Mann Whitney U test was usedto calculate differences in the mean for binomial non-parametricdata and Kruskal–Wallis test when comparing more than twoindependent samples. Chi square tests were used to comparecategorical data.

3. Results

One hundred midwives and doctors (61 midwives and 39doctors) were invited and all agreed to participate in this study. Ofthe 61 midwives, 55 were junior (Band 5 and 6) and six were seniormidwives (Band 7 and 8). Twenty-one doctors were trainees and15 were consultants or had completed their specialist training.Thirty-two percent of participants had less than one year of clinicalexperience, 42% had between one and ten years’ experience and26% more than ten years’ experience. Seventy-six percent hadundergone formal training in performing episiotomies.

Nearly 70% of accoucheurs (55 (90%) midwives and 14 (45%)doctors) had undertaken fewer than five episiotomies beforeindependent practice (Table 1) and only 37% had done more thanten episiotomies unsupervised.

Both doctors and midwives stated that in their clinical practicethey would perform a mediolateral episiotomy at an angle of 45degrees from the midline (Table 2), but only 25 accoucheurs stated

they would incise them at an angle of 60 degrees or more from themidline. While doctors subsequently depicted an angle of 45degrees, however, midwives drew episiotomies that were actuallyeight degrees closer to the midline. In addition midwives drewepisiotomies that were shorter by 1.3 cm and ended 1.5 cm closerto the midpoint of the anal canal.

The main indications stated for performing episiotomies wereto expedite delivery (31%), prevent OASIS (26%) and fetal distress(23%). The main concerns expressed about performing episio-tomies were anal sphincter extension (36%), bleeding (35%) andinfection (15%). Significantly more doctors were concerned thatepisiotomies may lead to anal sphincter damage (30 (77%) vs. 6(10%), p < 0.01), while midwives were more worried thatepisiotomies caused infection (14 (23%) vs. 1 (3%), p < 0.01).

While 13 (21%) midwives and all the doctors claimed to knowwhich muscles are routinely cut when performing a mediolateralepisiotomy; none of the midwives and only 18% of doctors knewthat the superficial transverse perineal and bulbospongiosusmuscles were involved.

Training courses had no impact on how an episiotomy wasperformed (Table 3). However, accoucheurs who had beensupervised for at least ten episiotomies before independentpractice performed episiotomies that were angled further awayfrom the midline and the anal canal (Table 4).

Episiotomy study

Role: Midwife Doctor

Rank: Band 5 Band 6 Band 7 Band 8

FY2 ST1-2 ST3-5 ST6-7 Post CCT

Fellow Consultant

Have you had formal training? At ASPH Elsewhere

How many episiotomies have you done unsupervised? 0-10 5-10 >10

How many episiotomies have you done unsupervised? 0-10 >10

Year experience: <1 1- 5 5-10 >10

How long would you make the cut for an episiotomy (cm) ………..………..…...

At what angle would you make a cut for an episiotomy? ………...…………..….

Why would you perform an episiotomy?...................……………………………..

…………………………………………………………………………………………..

What are you worried about when performing an episiotomy?...........................

…………………………………………………………………………………………..

What muscle or structures are routinely cut during at episiotomy that you

perform?..............................................................................................................…………………………………………………………………………………………..

Fig. 2. Interview administered proforma.

Table 3The impact of training on episiotomy technique.

Trained n = 76 Not trained n = 24 p-Value*

Described angle 45 (30–48.75) 45 (40.5–58.8) 0.25

Drawn angle 33.37 (20.2–49.03) 40.5 (34.1–49.4) 0.07

Length episiotomy 2.7 (2.05–3) 2.7 (2.13–3.68) 0.52

Distance from caudal end episiotomy to midline 1.1 (0.95–1.85) 1.65 (1.2–2.4) <0.01

Distance caudal end of episiotomy to midpoint anal canal 2 (0.6–3.25) 3 (1.73–3.8) 0.14

* Mann–Whitney U test.

Table 2Described and drawn angle of episiotomy.

Midwife n = 61 median (IQR) Doctor n = 39 median (IQR) p-Value*

Described angle 45 (30–57.5) 45 (45–56.3) 0.22

Drawn angle 37.3 (29.6–47.1) 44.9 (36.4–56.7) 0.013

Length episiotomy 2.3 (1.9–3) 3.6 (2.7–3.9) <0.01

Distance from caudal end episiotomy to midline 1.2 (1–1.8) 2.3 (1.3–3) <0.01

Distance caudal end of episiotomy to midpoint anal canal 2.5 (0–3.13) 4 (2.6–4.7) <0.01

IQR, interquartile range.* Mann–Whitney U test.

K.W. Wong et al. / European Journal of Obstetrics & Gynecology and Reproductive Biology 174 (2014) 46–5048

Table 4Differences in episiotomy technique depending on level of supervision prior to independent practice.

Number supervised episiotomies 0–5 Median (IQR) 5–10 Median (IQR) >10 Median (IQR) p-Value*

Described angle 45 (30–50) 45 (40–60) 45 (45–58.1) 0.12

Drawn angle 39.2 (29.3–8.6) 37 (31.8–41.2) 47.8 (36.2–0.4) 0.02

Length episiotomy 2.5 (2–3.2) 2.9 (2.2–3.7) 3.4 (2.3–3.8) 0.09

Distance from caudal end episiotomy to midline 1.4 (1.1–2) 1.7 (1.3–2.2) 2.3 (1.3–3.1) 0.01

Distance caudal end of episiotomy to midpoint anal canal 2.5 (0–3.2) 2.7 (1.7–3.7) 4 (3.1–4.5) <0.01

* Kruskal–Wallis test.

K.W. Wong et al. / European Journal of Obstetrics & Gynecology and Reproductive Biology 174 (2014) 46–50 49

4. Comment

Anal incontinence is a social stigma that can have a devastatingimpact on a woman’s quality of life. It is apparent that the angle atwhich an MLE is incised is important; and that it should be at least60 degrees from the midline to protect against OASIS [13]. Thisstudy demonstrates that while three-quarters of doctors andmidwives have undergone training, they were unaware of theappropriate angle to perform an MLE.

Doctors and midwives in our study said they would perform anMLE at 45 degrees from the midline. While an angle of 45 degreesfrom the midline appears to be an appropriate for an MLE aftersuturing, the angle at which an MLE should be cut at protectagainst OASIS should be at least 15 degrees further than that fromthe midline [13,15]. In addition there is discrepancy between theway midwives described and the way they depicted angles. Whiledoctors described and subsequently drew an episiotomy at 45degrees from the midline, midwives drew them eight degreescloser to the midline than they described. The difference in anglesof performing an MLE between doctors and midwives has beenhighlighted previously. Tincello et al. [10] used a validated pictorialquestionnaire and found that midwives drew episiotomies thatwere significantly closer to the midline than doctors. Subsequentto this Andrews et al. [12] measured the angle of episiotomiesperformed by doctors and midwives in routine clinical practice inSouth London and showed that midwives angled and performedepisiotomies closer to the midline and the anal sphincter thandoctors.

Three-quarters of the accoucheurs in our study had undergoneformal training in episiotomies. Training in itself did not have animpact on the angle at which an MLE was drawn. Hands-onperineal and episiotomy repair courses have previously beenevaluated [16,17,19]. These courses have been shown to improveparticipants’ knowledge of the anatomy of the perineum and analsphincter. They also have demonstrated that participants changedtheir clinical practice of episiotomy repair to evidence-basedmedicine after attending such workshops, reducing the rates ofperineal pain wound infection and women needing sutureremoval. None of these courses, however, have evaluated theangle at which an episiotomy should be incised.

In our study we found that doctors and midwives whoperformed mediolateral episiotomies independently after beingsupervised for at least ten episiotomies performed ones that werein keeping with the angle they described, whereas those with lessexperience depicted episiotomies that were significantly moreacute. Practitioners who had done between five and tenepisiotomies before independent practice performed them nearlyten degrees closer to midline; suggesting that the number ofepisiotomies performed before independent practice is important.

In the United Kingdom, work-based assessments have beenintroduced for practical procedures in Obstetrics and Gynaecology[20]. This takes the form of competency-based training, after whichan individual is deemed to be able to perform a procedureindependently. While competency-based training has never beenevaluated in a clinical trial, it is replacing the traditional system ofexperience gained by the number of procedures performed by an

individual. Our study indicates that while competency-basedtraining is important, a stated minimum number of proceduresundertaken by an individual before independent practice alsoneeds to be taken into consideration.

As already highlighted, the risk of OASIS is determined by theangle of a mediolateral episiotomy. Nearly 80% of doctors wereconcerned that a mediolateral episiotomy could lead to OASIS, butonly 10% of midwives believed this to be a significant problem.While only one doctor was concerned that episiotomies causedperineal infections, a quarter of midwives felt this to be a worry.The Cochrane review [21] evaluating high quality clinical trialsfound that the rate of perineal infection did not differ whether apolicy of restrictive or routine episiotomy was adopted. Thistherefore suggests that episiotomy per se does not cause perinealinfections.

Our study revealed that knowledge of perineal anatomy amongaccoucheurs is poor, despite widespread introduction of training inperineal repair for both doctors and midwives. These findings echothose of Sultan et al. [16] from 20 years ago, when 75 midwives and75 doctors were interviewed. Two thirds of the doctors inter-viewed in that study were clinically experienced obstetricians intraining.

We acknowledge that using a pictorial representation of theperineum may not represent exactly what accoucheurs do inclinical practice. However, the difference between midwives anddoctors in the angle of performing an episiotomy has beenhighlighted previously [12], and therefore we believe that ourfindings are representative of current practice. The strengths of ourstudy were the fact that all midwives and doctors agreed to takepart in the study, and that the investigator calculating the angle ofan MLE was blinded to the angle initially stated by the participant.

In conclusion, the risk of OASIS is higher when an MLE is angledcloser to the midline. Ninety percent of the accoucheurs in ourstudy were unaware that the angle of incision of an MLE should beat least 60 degrees from the midline in order to reduce the risk ofOASIS. In addition there is a discrepancy between the describedand depicted angles of an MLE by midwives. As competency-basedtraining is being progressively introduced into obstetrics ourfindings suggest that midwives and doctors should perform at leastten supervised episiotomies prior to independent practice, andthat courses should be an adjunct and not a substitute for hands-onclinical training. We acknowledge that there is no current evidencethat training can improve the visual accuracy of estimating theincision angle at crowning. Such training programmes should bedevised and validated. Consideration should be given to thedevelopment of novel surgical devices that help the accoucheur toperform a MLE accurately.

Conflict of interests

We have no conflicts of interest to declare.

Funding

No funding was obtained for this study.

K.W. Wong et al. / European Journal of Obstetrics & Gynecology and Reproductive Biology 174 (2014) 46–5050

Acknowledgements

We thank all of the doctors and midwives who participated inthe study.

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