Postpartum hemorrhage caused by trauma to the birth canal is obvious in most cases. Important exceptions are unrecognized accumulations of blood within the uterus or vagina as well as uterine rupture with intraperitoneal bleeding. Initial assessment strives to differentiate uterine atony from genital tract lacerations. An understanding of predisposing risk factors shown in Table 30-1 can aid this discrimination. It is axiomatic that persistent bleeding despite a firm, well-contracted uterus suggests that hemorrhage most likely is from lacerations. Bright red blood further suggests arterial bleeding. To confirm that lacerations are a source of bleeding, careful inspection of the vagina, cervix, and uterus is essential.

Sometimes bleeding may be caused by both atony and trauma, especially after forceps- or vacuum-assisted vaginal delivery. Importantly, if significant bleeding follows these types of deliveries, then the cervix and vagina should be carefully examined to identify lacerations. This is easier if epidural or spinal analgesia has been placed for labor and delivery. If no lower genital tract lacerations are found and the uterus is contracted yet supracervical bleeding persists, then manual exploration of the uterus is done to exclude a uterine tear. This is also done routinely after internal podalic version and breech extraction.

Vulvovaginal Lacerations

Childbirth is invariably associated with some trauma to the birth canal, which includes the uterus and cervix, vagina, and perineum. Injuries sustained during labor and delivery range from minor mucosal abrasions to lacerations that create life-threatening hemorrhage or hematomas.

Small tears of the anterior vaginal wall near the urethra are relatively common even after the most uncomplicated deliveries, especially in nulliparas. They are often superficial with little or no bleeding, and suture repair is usually not necessary. That said, minor superficial perineal and vaginal lacerations occasionally require sutures for hemostasis. A fine-gauge absorbable suture such as 4-0 gauge plain or chromic gut is suitable. Adequate analgesia is necessary to repair such lesions.

Deeper perineal lacerations are usually accompanied by varying degrees of injury to the outer third of the vaginal vault. Some extend to involve the anal sphincter or varying depths of the vaginal walls. The frequency of third- and fourth-degree lacerations in more than 87,000 deliveries from the Consortium on Safe Labor database is shown in Table 30-2. Some factors associated with an increased frequency of lacerations are also shown in the table. One of these is parity, and the frequency of these perineal lacerations was 5.7 percent in nulliparas but only 0.6 percent in multiparas. Lacerations were also more common with operative vaginal delivery, episiotomy, increasing newborn birthweight, and prolonged second-stage labor (Fong, 2014; Landy, 2011; Laughon, 2014). Episiotomy, perineal laceration, and their repair are discussed in detail in Chapter 20 (p. 320).

Bilateral vaginal lacerations are usually unequal in length, and they are separated by a tongue of vaginal tissue. Lacerations involving the middle or upper third of the vaginal vault usually are associated with injuries of the perineum or cervix. Cervical tears sometimes are missed unless thorough inspection of the upper vagina and cervix is performed. It is worth repeating that bleeding despite a firmly contracted uterus is strong evidence of a genital tract laceration. Vaginal lacerations that extend upward usually are longitudinal. They may follow spontaneous delivery but frequently result from injuries sustained during operative vaginal delivery with forceps or vacuum extractor. Most involve deeper underlying tissues and thus usually cause significant hemorrhage. Bleeding is typically controlled by appropriate suture repair. For this, a running locking suture line begins at the proximal apex of the laceration and progresses distally. In most instances a single-layer closure using a 0- or 2–0 gauge absorbable suture such as chromic gut or polyglactin 910 (Vicryl) is sufficient. Persistent bleeding sites may require selectively placed figure-of-eight sutures for hemostasis.

Extensive vaginal or cervical tears should prompt a careful search for evidence of retroperitoneal hemorrhage or peritoneal perforation with hemorrhage. An extreme example of a posterior fornix tear reported by Sakhare and colleagues (2007) is shown in Figure 30-1. If such a perforation is suspected, laparotomy should be considered (Rafi, 2010). Extensive vulvovaginal lacerations also warrant uterine exploration for possible uterine tears or rupture. For deep vulvovaginal lacerations, effective analgesia or anesthesia, vigorous blood replacement, and capable assistance are mandatory during suture repair. In the study reported by Melamed and associates (2009), 1.5 percent of women with these lacerations required blood transfusions. Postoperative infections are also common in these women (Lewicky-Gaupp, 2015). With any of the lacerations discussed in this section, those large enough to require extensive repair are typically associated with voiding difficulty. A postoperative indwelling bladder catheter will obviate this. In most cases, the catheter can be removed the following day.

Levator Sling Injuries

The levator ani muscles, described in Chapter 3 (p. 35), are usually involved with deep vaginal vault lacerations. Muscle fibers are torn and separated, and their diminished tone may interfere with pelvic diaphragm function to cause pelvic relaxation. In one review, the levator ani muscles were reported to be injured in 13 to 36 percent of women who had a vaginal delivery (Schwertner-Tiepelmann, 2012). In a recent study of nulliparas who underwent operative vaginal delivery—247 vacuum-assisted and 42 forceps deliveries—20 percent had a levator injury. In these women, operative vaginal delivery was the only identifiable risk factor (Chung, 2015). In addition, stretch injuries may also result from overdistention of the birth canal.

The long-term quality of life of these women has not been well studied. However, if the injuries involve the pubococcygeus or puborectalis muscles, urinary and anal incontinence also may result, although the exact incidence is unknown.

Cervical Lacerations

Superficial lacerations of the cervix can be seen on close inspection in more than half of all vaginal deliveries. Most of these are less than 0.5 cm and seldom require repair (Fahmy, 1991). Deeper lacerations are less frequent, but even these often are unnoticed. Due to ascertainment bias, variable incidences are described. For example, in the Consortium on Safe Labor database that included deliveries in which close inspection was employed, the incidence of cervical lacerations was 1.1 percent in nulliparas and 0.5 percent in multiparas (see Table 30-2). This contrasts with an overall incidence of only 0.16 percent reported by Melamed and coworkers (2009), whose study included more than 81,000 Israeli women. In another study, Parikh and associates (2007) reported a 0.2-percent incidence of cervical lacerations that required repair.

Such lacerations may be related to operative vaginal delivery, especially with the use of forceps. For example, in a recent study from California of trends and morbidity associated with operative vaginal delivery, higher rates of cervical laceration repair were reported with forceps use compared with vacuum delivery (Fong, 2014).

Cervical lacerations are not usually problematic unless they cause hemorrhage or extend to the upper third of the vagina. Rarely, the cervix may be entirely or partially avulsed from the vagina—colporrhexis—in the anterior, posterior, or lateral fornices. These injuries sometimes follow difficult forceps rotations or deliveries performed through an incompletely dilated cervix with the forceps blades applied over the cervix. In some gravidas, cervical tears reach into the lower uterine segment and involve the uterine artery and its major branches. They occasionally extend into the peritoneal cavity. The more severe lacerations usually manifest as external hemorrhage or as a hematoma, however, they may occasionally be unsuspected. In the large Israeli study reported by Melamed and colleagues (2009), almost 11 percent of women identified as having a cervical laceration required blood transfusions.

Other serious cervical injuries fortunately are uncommon. In one, the edematous anterior cervical lip is caught during labor and compressed between the fetal head and maternal symphysis pubis. If this causes severe ischemia, the anterior lip may undergo necrosis and separate from the rest of the cervix. Another rare injury is avulsion of the entire vaginal portion of the cervix. Such annular or circular detachment of the cervix is seen with difficult deliveries, especially forceps deliveries.

Diagnosis

A deep cervical tear should always be suspected in women with profuse arterial hemorrhage during and after third-stage labor, particularly if the uterus is firmly contracted. It is reasonable to inspect the cervix routinely following major operative vaginal deliveries even if there is no third-stage bleeding. Thorough evaluation is necessary, and often the thinned, floppy cervix interferes with digital examination. The extent of the injury can be more fully appreciated with adequate exposure and visual inspection. This is best accomplished when an assistant applies firm caudal-directed pressure on the uterus, and the operator exerts traction on the lips of the cervix with ring forceps. A second assistant can provide improved exposure with right-angle vaginal wall retractors.

Management

In general, cervical lacerations measuring 1 and even 2 cm are not repaired unless they are bleeding. Such tears heal rapidly and are thought to be of no significance. When healed, the external cervical os has an irregular, sometimes stellate, appearance.

Deep cervical tears usually require surgical repair. When the laceration is limited to the cervix or even when it extends somewhat into the vaginal fornix, satisfactory results are obtained by suturing the cervix after bringing it into view at the vulva (Fig. 30-2). While cervical lacerations are repaired, associated vaginal lacerations may be tamponaded with gauze packs to arrest their bleeding. Because hemorrhage usually comes from the upper angle of the wound, the first suture using absorbable material is placed in tissue above the angle. Subsequently, either interrupted or continuous locking sutures are placed outward toward the operator. Either delayed-absorbable or absorbable suture is suitable, and 0- or 2-0 gauge chromic gut or polyglactin 910 is a reasonable choice. If lacerations extend to involve the lateral vaginal sulcus, then attempts to restore the normal cervical anatomic appearance may lead to subsequent stenosis.

Most cervical lacerations are successfully repaired using sutures. However, if there is uterine involvement and continued hemorrhage, then some of the methods described in Chapter 29 (p. 475) may be necessary to obtain hemostasis. For example, Lichtenberg (2003) described successful angiographic embolization for a high cervical tear after failed surgical repair. In other cases, laparotomy and even hysterectomy may be necessary to obtain hemostasis.

Pelvic hematomas following childbirth are most often associated with a laceration, episiotomy, or an operative vaginal delivery. That said, some may develop following stretch and rupture of a blood vessel without associated lacerations (Nelson, 2012; Propst, 1998; Ridgway, 1995). These hematomas may have any of several anatomic manifestations. In some cases, they are quickly apparent, but in others, hemorrhage may be delayed. Occasionally, they are associated with an underlying acquired coagulopathy such as with placental abruption or acute fatty liver of pregnancy, from therapeutic anticoagulation, or from a congenital bleeding disorder such as von Willebrand disease.

One anatomy-based classification of puerperal hematomas includes vulvar, vulvovaginal, paravaginal, supralevator, ischioanal, and retroperitoneal hematomas (Fig. 30-3). Vulvar hematomas most often involve branches of the pudendal artery. The three main divisions are the inferior rectal artery, the dorsal artery of the clitoris, and the perineal artery, including its posterior labial artery branch (Fig. 3-7, p. 36). Paravaginal hematomas may involve the descending branch of the uterine artery (Zahn, 1990). In some cases, a torn vessel lies above the levator ani muscles, and a supralevator hematoma develops. These can extend into the upper portion of the vaginal canal and may almost occlude its lumen. Continued bleeding may dissect up the retroperitoneal space to form a mass palpable above the inguinal ligament. Finally, it may even dissect up behind the ascending colon to the hepatic flexure at the lower margin of the diaphragm (Rafi, 2010).

Vulvovaginal Hematomas

Hematomas of the perineum, vulva, and paravaginal spaces can develop rapidly. They frequently cause excruciating pain, as did the one shown in Figure 30-4. If bleeding ceases, then small- to moderate-sized hematomas may be absorbed. In others, the tissues overlying the hematoma may rupture from pressure necrosis. At this time, profuse hemorrhage can follow. In other cases, the hematoma drains in the form of large clots and old blood. In those that involve the paravaginal space and extend above the levator plate, retroperitoneal bleeding may be massive and occasionally fatal. Finally, we have occasionally encountered hematomas that re-bled up to 2 weeks postpartum, such as the woman shown in Figure 30-5.

Diagnosis

A vulvar hematoma is usually readily diagnosed because of severe perineal pain. A tense, fluctuant, tender swelling of varying size rapidly develops and is eventually covered by bruised, discolored skin. A paravaginal hematoma may escape detection temporarily. But symptoms of pelvic pressure, pain, or inability to void warrant evaluation and lead to discovery of a round, fluctuant mass encroaching on the vaginal lumen. When there is supralevator extension, the hematoma extends upward through the paravaginal space and then between the leaves of the broad ligament (Fig. 30-6). In some women, the hematoma may escape detection until it can be felt on abdominal palpation or until hypovolemia develops. Imaging with sonography or computed tomographic (CT) scanning can be useful to assess hematoma location and extent (Kawamura, 2014; Takeda, 2014). As discussed subsequently, supralevator hematomas are particularly worrisome because they can be fatal.