Episiotomy is a surgical enlargement of the vaginal orifice by an incision to the perineum during the last part of the second stage of labor or delivery [7, 9]. It should always be defined by the following combination of parameters; the location of the beginning of the incision, the direction, the length, and the exact timing of the procedure. A recent analysis [10] revealed that the standard research texts usually describe only two main types of episiotomy (midline and mediolateral) [9, 11–13]. The term lateral episiotomy has only lately started to be re-used [14–19]. Therefore, a classification system of episiotomies [10] is important in order to improve the quality of methodology in future research and to facilitate the comparison of different studies.

A thorough analysis of the literature [10] revealed seven main types of episiotomy: midline, modified median, J-shaped, mediolateral, lateral, radical lateral, and anterior (Fig. 6.2).

Midline (median, medial) episiotomy begins at the fourchette and extends to a half of the length of the perineal body [10, 11, 20].

Modified median episiotomy differs from the previous type by two transverse cuts in opposite directions slightly anteriorly of the expected margins of the external anal sphincter (EAS) [21]. Transversely, only subcutaneous tissues, not the skin, may be incised.

“J-shaped” episiotomy runs initially as a midline incision and then at approximately 2.5 cm from the anus is curved to avoid the anal sphincter [10, 22, 23]. The latter part of episiotomy is directed towards the ischial tuberosity [24].

Mediolateral episiotomy is a compromise between midline and lateral episiotomy. The results of recent research clearly demonstrate that the definition of mediolateral episiotomy has thus far been unsatisfactory [25–31]. A wide variety in the clinical performance of mediolateral episiotomy has been observed between countries and institutions [29] as well as between individual doctors and midwives [27, 28]. Based on studies by Tincello et al. [27], Eogan et al. [32], and Kalis et al. [30, 33] evaluating the placement of episiotomy, an angle of episiotomy of 60° has been proposed as part of the definition [10]. Therefore, mediolateral episiotomy is defined as an incision starting at the posterior fourchette in the midline and directed at an angle of at least 60° towards the ischial tuberosity [10, 33].

Lateral episiotomy begins in the vaginal introitus 1–2 cm laterally from the midline and is directed towards the ischial tuberosity [24, 34–37]. Lateral episiotomy is often non-mentioned in obstetric literature [8, 11, 12, 38]. This type has been reported in only one RCT [19]. The Cochrane review [9] suggests that: “There is a pressing need to evaluate which episiotomy technique (mediolateral or midline) provides the best outcome” thus not taking lateral episiotomy into account [9]. Also, a review analyzing seven commonly sold general textbooks [39] evaluates whether “both methods of performing episiotomy (median/mediolateral)” are discussed in the texts, so again no other type of episiotomy is mentioned. However, it has been found that lateral episiotomy has in fact been used, albeit unintentionally by wider medical community, in Europe [28, 29]. In both Finland and Greece this type of episiotomy is used routinely [14, 40, 41].

Radical lateral (Schuchardt incision) is an original non-obstetrical episiotomy performed at the beginning of radical vaginal hysterectomy or trachelectomy [42–44], starting as lateral episiotomy but passing around the rectum in a downward, lateral curve [45]. Only rarely it is recommended as an aid to childbirth during complicated deliveries [35, 37, 45].

Anterior episiotomy (deinfibulation – opening the scar associated with female genital mutilation). A potential choice for labour and also antenatally [20, 46], the anterior scar tissue is incised in the midline up to the urethra [47]. Due to the possibility of tissue stretching at the end of delivery, it may be deemed necessary to employ an alternative type of episiotomy.

To improve the methodological quality of studies evaluating episiotomy, the authors present the following proposal for a detailed classification of episiotomies, Table 6.1.

An evaluation of studies and reviews, where the majority focussed on mediolateral episiotomy, has found that the methodology is very often poorly organised [48]. Four main problems were defined: diagnostics and classification of the perineal trauma, and the definition and practical implementation of mediolateral or lateral episiotomy [48]. Evaluating the methodology of studies included in the Cochrane review [9], only two studies looked at median episiotomy [49, 50], and none of the others described the positioning of mediolateral episiotomy sufficiently [25, 51–55], suggesting that the methodology did not fulfill current requirements and no clear conclusions may be drawn, especially with regards to severe perineal trauma.

There is growing evidence that the exact placement of episiotomy plays an important role in the degree of perineal trauma [14, 15, 32, 57–59]. At crowning, the perineal body is particularly exposed to a high degree of deformation. After delivery, the strain on the perineal tissues and edema recedes, and subsequently the deformation disappears. The significant alterations in the geometry of the perineal region result in a difference between the observed episiotomy locations: at the time of incision, after repair, and later postpartum [59]. Based on perineo-anthropometric studies [30, 32, 33] three new terms have been introduced: incision angle, suture angle and scar angle of episiotomy [33]. It has been shown that a mean incision angle of 40° falls to 20° after suture [30] while that of 60° falls to 45° [33]. Analysis showed a 50 % relative reduction in the risk of obstetric anal sphincter injuries (OASIS) for every 6.3° that the episiotomy scar lies away from the perineal midline [32]. This finding was later supported by Stedenfeldt who also found that episiotomy cut too short and at too wide an angle also carried a higher risk of OASIS [56].

In many retrospective studies [60–63] as well as in a recent RCT [50] midline episiotomy was associated with an increased risk of OASIS and consequent functional damage. A significantly higher incidence of OASIS was also found for midline episiotomy in comparison to the mediolateral type [26, 64–67]. Mediolateral episiotomy has consistently been found to be protective in instrumental vaginal deliveries [68–70] whereas midline episiotomy has been associated with a significant increase in OASIS [71]. Lateralisation of episiotomies as a part of a set of obstetric interventions contributed to an immediate significant decrease in OASIS in Norway [57, 58, 72]. Lateral episiotomies have consistently been found to be protective in primiparous women [16, 17], the effect of mediolateral episiotomies has differed between studies [73–77], and midline episiotomy has never been found protective [7, 9, 78, 79]. A recent RCT evaluating properly performed mediolateral and lateral episiotomies has shown a low incidence of OASIS amongst primiparous women [80]. Two procedures that appear to be among those that best divert principal perineal tissue strain away from the midline appear to be appropriately executed mediolateral episiotomy as well as properly executed lateral episiotomy [80].

The performance of episiotomy to expedite delivery in cases of non-reassuring fetal status by shortening the second stage of labour is currently a generally accepted approach. There does however remain a lack of professional consensus regarding other specific episiotomy indications. The commonly argued goals and indications include:

Traditionally, episiotomy has been a routine component of instrumental delivery, the primary aim being to avoid OASIS. However, the use of instrumental delivery in combination with midline episiotomy was associated with a significant increase in the risk of OASIS in both primiparous and multiparous women [71]. Time trends support a reduction in OASIS by restricting the liberal use of the two modifiable variables: midline episiotomy and forceps delivery [100].

Routine use of mediolateral episiotomy in instrumental delivery is recommended by the National Institute for Health and Care Excellence (NICE) [101]. National surveys in the UK and Ireland revealed that two-thirds of obstetricians held the view that routine use of episiotomy decreases the likelihood of OASIS for a forceps delivery while having a divided view as to vacuum extraction [102]. In the only RCT comparing routine versus restrictive use of episiotomy for instrumental delivery, routine use of episiotomy was not associated with a statistically significant difference in the incidence of OASIS (8.1 % vs. 10.9 %) [103]. However, subsequently and with regards to the same population, Macleod et al. [104] found that restrictive use of episiotomy for instrumental delivery may increase immediate postpartum morbidity, in particular the incidence of perineal pain and stress urinary incontinence. The type of episiotomy or its precise placement were not recorded and neither were the complete spectrum of other obstetric interventions [103, 104].

Two large retrospective population-based register studies from the Netherlands suggested that mediolateral episiotomy reduces the risk of OASIS in instrumental delivery [68, 69]. De Leeuw et al. demonstrated that mediolateral episiotomy significantly protected against OASIS in both vacuum extraction and forceps [68]. Twelve mediolateral episiotomies were needed to prevent one case of OASIS concerning vacuum extraction, whereas five mediolateral episiotomies could prevent one case of OASIS with regards to forceps. Another Dutch group found a sixfold decrease in the risk of OASIS when mediolateral episiotomy was performed in women undergoing instrumental deliveries [69]. According to this study, the known adverse effects of mediolateral episiotomy (e.g., short-term perineal pain, dyspareunia) cause less morbidity compared with the known adverse effects of OASIS (e.g., fecal incontinence).

In a similar Finnish study evaluating vacuum extraction, lateral episiotomy decreased the incidence of OASIS by 46 % in primiparous but not in multiparous women [17].

Although there is a growing general consensus about restricting the use of episiotomy, no such agreement has emerged as to what constitutes an appropriate episiotomy rate [105]. Carroli and Belizán have established that a restrictive episiotomy rate above 30 % is not clinically justified [25]. Episiotomy rates around the world range from as low as 9.7 % in Sweden to 100 % in Taiwan, while half of all countries exceeded the recommended rate of 30 % [40, 105]. Moreover, episiotomy rates vary with regards to parity. Results from large epidemiologic studies from restrictive episiotomy settings where total episotomy rate remained under 30 % showed an episiotomy rate of 55–65 % in primiparous women [106, 107].

When defining the lower limit for “safe” episiotomy rate, it is important to take into account the type of episiotomy being used and the quality indicator for determining the success of the restrictive approach. The quality indicator commonly used is the OASIS rate.

In the USA, a restrictive approach to midline episiotomy in spontaneous deliveries resulted in a reduction in the OASIS rate from 5 to 3.5 % [108]. In Australia a significant correlation was registered between increasing mediolateral episiotomy use, from 12.6 to 20.1 %, and a reduction in the OASIS rate, from 4.4 to 2.1 % [109]. Both lateral (in Finland and Norway) and mediolateral episiotomy (in Sweden, Denmark and Norway) are used in Nordic countries. Within the last 10 years a falling trend in the use of episiotomy was registered in Denmark (10 % vs. 5 %) and Sweden (9 % vs. 6 %) while the rate remained unchanged in Norway (20 % vs. 19 %) and stayed higher in Finland (42 % vs. 24 %). However, OASIS incidence in Finland has been notably lower (0.7–1 %) than in the other Nordic countries (2.3–4.2 %). A significant and constant reduction in OASIS incidence has only been observed in Norway (from 4.1 to 2.3 %, p < 0.001) [110, 111]. This reduction occurred simultaneously with the introduction of a national intervention program of improved delivery techniques aiming at reducing the incidence of OASIS [57, 111].

The optimal time for performing an episiotomy is unclear and depends largely on the indication. In cases where prophylactic episiotomy is performed, i.e. to facilitate a forceps delivery or to expedite delivery, it is recommended to perform episiotomy when the head is visible during a contraction to a diameter of 3–4 cm [20]. However, with restrictive approach to episiotomy, the indication often arises during the crowning. It is important to bear in mind the significant difference in the change of the angle of mediolateral episiotomy between time of cut and after repair depending on the timing of the episiotomy [30]. Performing episiotomy early before crowning of the fetal head is associated with increased blood loss [112]. Some authors have argued that performing episiotomy too late compromises the protection of the maternal perineum. According to their opinion, at the time of crowning, the fetal head has already torn the perineal muscles and the damage of the supporting structures has already occurred [24, 113]. However, no valid studies have been performed to support this expert opinion.

Reduction of maternal discomfort during episiotomy repair and short- and long-term maternal morbidity following this procedure can be achieved with the use of an appropriate type of analgesia, the choice of quality suture materials and the application of modern suturing techniques.

The level of analgesia/anaesthesia should be adequate for the episiotomy repair. If the patient received an adequate epidural anaesthesia during labour, it can be used to provide analgesia for the repair. Pudendal nerve block or local field block is generally adequate if there is no pre-existing analgesia.

Several studies have shown the advantages of fast-absorbing polyglactin 910 for episiotomy repair [114–117]. Meta-analysis revealed that, comparing standard synthetic with fast-absorbing sutures for repair of episiotomy and second-degree tears, short- and long-term pain scoring was similar [118]; in one trial fewer women with fast-absorbing sutures reported using analgesics at 10 days (RR 0.57) [117]. More women in the standard synthetic group required suture removal compared to those in the fast-absorbing group (RR 0.24) [117, 118].

For more than 80 years, researchers have been suggesting that continuous non-locking suture techniques for repair of the vagina, perineal muscles and skin are far better than “traditional” interrupted methods in terms of reduced postpartum pain [117, 119–121]. Recent meta-analysis showed that continuous suture technique, when compared with interrupted sutures for episiotomy or second-degree tear repair (in all layers or perineal skin only), are associated with less perineal pain for up to 10 days postpartum (RR 0.76) [122]. There was an overall reduction in analgesia use associated with the continuous subcutaneous technique versus interrupted stitches for repair of perineal skin (RR 0.70). There was also a reduction in suture removal in the continuous suturing groups versus interrupted (RR 0.56), whereas no significant differences were seen in the need for re-suturing of wounds or in long-term pain.

Several case studies and one small randomized trial have suggested that tissue adhesives could be used instead of stitches for episiotomy repair [123–126]. However, these agents are expensive and not all are widely available so further research is needed to determine the safety and efficacy of this approach.

Complications can occur in any healing process. In episiotomy and/or any degree of perineal trauma, the following variables are usually evaluated: episiotomy dehiscence and need for surgical re-intervention, infection of episiotomy and need for antibiotic treatment, haematoma in episiotomy, and the need for removal of suture material [9]. These variables have not been evaluated in any significant detail and extensive data are not available due to the relatively low prevalence of these complications which vary between 0.1 and 2.1 % [127–130].

For an overall evaluation of healing complications in episiotomy suture, the REEDA scale is generally used [131] in spite of some limitations to the interrater reliability evaluation [132]. This scoring system contains five domains: redness, edema, ecchymosis, discharge and approximation of the edges of the suture [131].

Episiotomy is a common cause of postpartum perineal pain [9, 26, 55, 151, 152]. The presence and intensity of the pain is associated with the degree of perineal injury [151, 153–155], instrumental delivery, parity, duration of delivery [152, 156], type of suturing material [114–116, 118] repair technique [117, 122] or analgesia used [157–164]. Currently, the most commonly used scoring systems are two components of SF-MPQ [165]: The Visual Analogue Scale (VAS) and Present Pain Intensity (PPI), and the four-point Verbal Rating Score (VRS) [166].

Post-episiotomy pain affects up to 97 % of women on the first day [26, 152] and up to 71 % of women 7–10 days postpartum [152]. Comparing routine and restrictive approaches, the current version of the Cochrane review [9] has found a higher incidence of pain in the routine approach at discharge [25] but no difference at 3 and 10 days and 3 months postpartum [54, 55]. Women with a routine approach to episiotomy registered more maximum intense pain within the first 5 days postpartum [51]. However, in the long term, there was no difference observed in the prevalence of perineal pain between routine and restrictive approaches [167, 168].

There are very few studies comparing different types of episiotomy and perineal pain. In a quasi-randomized trial comparing midline and mediolateral episiotomies no difference in pain was observed 3 months after delivery [26]. The only study, with a retrospective design, evaluating perineal pain after mediolateral and lateral episiotomies and only one day postpartum found no difference in perception of pain [18].

When deliveries with episiotomy were compared to deliveries without episiotomy, the incidence of short-term episiotomy pain was similar on the 1st, 7th or 10th postpartum day regarding spontaneous first- and second-degree perineal tears, but higher than figures for an intact perineum and lower than those for OASIS [151, 152]. No difference was observed at 6 weeks [152]. At 3 months the incidence of post-episiotomy perineal pain was similar compared to spontaneous first- and second-degree tears but the frequency and intensity were higher in the episiotomy group [151].

Any childbirth, and particularly vaginal delivery, may change the qualitative level of sexual function. There are many sexual function related outcome measures to be followed. The main sexual components – desire, arousal, lubrication, orgasm, satisfaction and pain – are included in the most common tool used to evaluate postpartum sexuality, the Female Sexual Function Index (FSFI) [176]. Another scoring system frequently used is the McCoy Female Sexuality Questionnaire [177].

Apart from episiotomy and perineal trauma, sexual function after delivery can be subject to other variables: maternal age [178–180], partnership status [180, 181], breastfeeding [151, 179, 181–186], overall health and mental [181, 187] and physical status (including the partner’s) [180], pre-pregnancy dyspareunia [182, 183, 188], instrumental delivery [189, 190] or parity [151, 181, 191, 192].