What are the indications for performing an episiotomy?
What are the relative advantages and disadvantages of the various types of episiotomies?
What steps can be taken during the repair of third- and fourth-degree perineal lacerations to reduce the risk of complications?
What steps can be taken during the postpartum period for patients with third- or fourth-degree perineal lacerations to reduce the risk of complications?
You are called to assess an 18-y.o. G1 at 40 0/7 weeks gestation in the second stage of labor. She has been pushing for over 2 hours, and while the nurse reports that the fetal vertex has descended to the +3 station, she also reports that the effectiveness of her expulsive efforts have started to wane. The FHR tracing has developed repetitive variable decelerations to the 60s. You examine the patient and discuss the situation with her, and ultimately decide to proceed with a forceps-assisted vaginal delivery.
Is an episiotomy indicated in this situation?
If so, what type of episiotomy should be cut, and at what point in the procedure?
Laceration of the perineum may occur with any vaginal delivery, and it is so common that repair of such lacerations is considered a routine part of immediate postpartum care. The risk of complications associated with perineal lacerations increases dramatically with the increased levels of anatomy affected. This fact, along with other theoretical benefits, led to the popularization of routine episiotomy in the United States in the 1920s and 1930s.1 Episiotomy, more precisely termed perineotomy, refers to the enlargement of the distal birth canal via incision of the perineum in order to facilitate delivery of the fetus. For reasons that will be explored in detail later in this chapter, routine episiotomy has fallen out of favor, but the procedure is still an important tool in the obstetric and gynecological (OB/GYN) hospitalist’s arsenal. The roles of the OB/GYN hospitalist as an expert physician in difficult or emergent deliveries and as a leader in perinatal quality and safety necessitate familiarity with current recommendations in both complex laceration repair and the use of episiotomy. The aim of this chapter is to provide an overview of current best practices related to both episiotomy and perineal laceration repair.
The perineal body is commonly injured during vaginal delivery. It is a midline, fibromuscular tissue mass that is approximately 2 to 4 cm deep and 2 to 4 cm in anteroposterior diameter and is located between the distal posterior vagina and the anus. It is comprised of the attachments of the bulbospongiosis and superficial, transverse perineal muscles and the external anal sphincter (Fig. 62-1). The blood supply to the perineum is derived from branches of the internal pudendal artery, approaching the perineal structures from lateral to medial (Fig. 62-2).2
The anal sphincter complex is located inferior to the perineal body and is made up of the external anal sphincter (EAS) and the internal anal sphincter (IAS). The EAS is a circular, striated/skeletal muscle that is under voluntary control. This muscle aids in the continence of the stool and flatus by applying a squeezing pressure to the anal canal. The EAS is innervated by the inferior rectal branch of the pudendal nerve (Fig. 62-2), so injury to this nerve during childbirth can lead to EAS dysfunction. The IAS is a longitudinally oriented smooth muscle under autonomic control, located between the EAS and the anal canal from just proximal to the superficial aspect of the EAS and extending 2.5 to 4 cm. This muscle is critical in maintaining anal continence at rest by providing constant, resting pressure to the anal canal.
Injury to the perineum during vaginal delivery can be classified into four degrees of laceration,3 as described in Table 62-1 and demonstrated in Fig. 62-3. Third- and fourth-degree perineal lacerations, also known as obstetric anal sphincter injuries (OASIS), have been associated with dramatically increased rates of anal incontinence 5 to 10 years after delivery compared with a cesarean control group [odds ratio (OR) 2.32, 95% confidence interval (CI) 1.27–4.26].4 Furthermore, evidence suggests that the severity of the perineal tear directly affects the frequency of loss of anal continence, with women who sustained a fourth-degree laceration reporting decreased control of their bowels 10 times more frequently than those who sustained a third-degree laceration (30.8% vs. 3.6%, respectively; p < 0.001).5 Unfortunately, OASIs are sometimes unavoidable, with estimates of third- and fourth-degree lacerations complicating 3.3% and 1.1% of vaginal deliveries, respectively.6 Risk factors for OASIs based on a meta-analysis of 22 studies are described in Table 62-2.
|First degree||Injury to perineal skin only|
|Second degree||Injury involving perineal muscles, but not involving the anal sphincter|
|Third degree||Injury to perineal muscles, including the anal sphincter complex|
|3a||Less than 50% of the EAS thickness torn|
|3b||More than 50% of the EAS thickness torn|
|3c||EAS and IAS torn|
|Fourth degree||Injury to perineal muscles, anal sphincter complex, and anorectal epithelium|
|Risk Factor||Degree of Risk|
|Forceps-assisted delivery||OR 5.50, 95% CI 3.17–9.55|
|Vacuum-assisted delivery||OR 3.98, 95% CI 2.6–6.09|
|Midline episiotomy||OR 3.82, 95% CI 1.96–7.42|
|Increased fetal birth weight||Mean difference between cases and controls 192.88 g, 95% CI 139.80–245.96 g|
|Primiparity||OR 3.24, 95% CI 2.2–4.76|
|Persistent occiput-posterior position||OR 3.09, 95% CI 1.81–5.29|
|Asian ethnicity||OR 2.74, 95% CI 1.31–5.72|
While ideally, the shared decision-making process surrounding the use of episiotomy should take place during the antepartum period and be documented in the patient’s birth preferences, the OB/GYN hospitalist often does not have the advantage of such proactive discussions. Obtaining informed consent, therefore, is complicated by both the complexity of the topic, including multiple types of episiotomies and resulting difficulty in interpreting available data, and the typical urgency of the clinical situation. However, at a minimum, the intent to cut and a brief rationale of the decision should be mentioned to the patient prior to making an episiotomy.
Historically, episiotomy was routinely performed with the intent of preventing anterior vulvar and severe perineal trauma by making a controlled, easily repaired enlargement of the distal vagina. However, based on data strongly associating the routine use of median episiotomy with increased rates of OASIs as well as on limited data associating the routine use of mediolateral episiotomy with increased rates of perineal pain and dyspareunia at 3 months postpartum, the American College of Obstetricians and Gynecologists (ACOG) recommends against the routine use of episiotomy.7 In addition, the Leapfrog Group, a national nonprofit organization that publicly grades hospitals and reports selected metrics, has included a target episiotomy rate of <5% in its analysis.8
There are no clear, nationally accepted lists of indications for episiotomies, but a list of possible indications is shown in Box 62-1. It is important to note that neither operative vaginal delivery nor shoulder dystocia alone is an accepted indication for performing an episiotomy, as available data does not support improvement in outcomes with universal use of episiotomy in these situations.7
Box 62-1 Indications for Episiotomy
Need to expedite delivery of the fetus
Fetal heart rate tracing concerning for fetal acidemia, or
Unable to monitor fetal heart rate (FHR), and
Fetal vertex at outlet
Multiple major risk factors for OASIS present (do not use median episiotomy), as listed in Table 63-2
Perineal tissue limits ability to perform shoulder dystocia-reducing maneuvers
Factors guiding the method of cutting an episiotomy involve protecting the fetal scalp and controlling with precision the angle and length of the cut. Sterile scissors should be grasped in the physician’s dominant hand. Bandage scissors are potentially easier to use due to the ability to position the blade with the blunt leading edge against the fetal scalp, but they are often not immediately available on vaginal delivery carts. Straight Mayo scissors, therefore, are most frequently used, but curved Mayo scissors may be preferred if a curved (J-shaped) episiotomy is planned. The physician positions two fingers between the perineum and the fetal head, with the space between the fingers delineating the vector of the planned cut, and slides the bottom blade of the scissors between the two fingers. An incision is then made (Fig. 62-4).