There are many predisposing risk factors and potential causes for hemorrhage immediately following delivery (Table 28-1). Approximately half of maternal deaths from hemorrhage are due to these immediate postpartum causes. When excess bleeding is encountered, a specific etiology should be sought. Uterine atony, retained placenta—including placenta accreta and its variants, and genital tract lacerations account for most cases of immediate hemorrhage.
TABLE 28-1. Predisposing Factors and Causes for Hemorrhage Immediately Following Delivery
Severe intrapartum or early postpartum hemorrhage is on rare occasions followed by pituitary failure (Sheehan syndrome), which is characterized by failure of lactation, amenorrhea, breast atrophy, loss of pubic and axillary hair, hypothyroidism, and adrenal cortical insufficiency. The incidence of Sheehan syndrome was originally estimated to be 1 per 10,000 deliveries. It appears to be even more rare today in the United States.
Traditionally, postpartum hemorrhage has been defined as the loss of 500 mL or more of blood after vaginal delivery or 1000 mL or more after cesarean delivery (Figure 28-1). The woman with normal pregnancy-induced hypervolemia usually increases her blood volume by 30 to 60 percent, which for an average-sized woman amounts from 1 to 2 L. Consequently, she will tolerate, without any remarkable decrease in postpartum hematocrit, blood loss at delivery that approaches the volume of blood she added during pregnancy. Whereas blood loss somewhat in excess of 500 mL is not necessarily an abnormal event for vaginal delivery, actual blood loss is usually twice the estimated loss. Thus, an estimated blood loss in excess of 500 mL should call attention to women who are bleeding excessively.
FIGURE 28-1 Blood loss associated with vaginal delivery, repeat cesarean delivery, and repeat cesarean delivery plus hysterectomy. (From Pritchard JA, Baldwin RM, Dickey JC, et al: Blood volume changes in pregnancy and the puerperium, 2. Red blood cells loss and changes in apparent blood volume during and following vaginal delivery, cesarean section, and cesarean section plus total hysterectomy. Am J Obstet Gynecol 84:1271, 1962.)
NORMAL CONTROL OF HEMORRHAGE AT THE PLACENTAL SITE
Near term, it is estimated that approximately 600 mL/min of blood flows through the intervillous space. With separation of the placenta, the many uterine arteries and veins that carry blood to and from the placenta are severed abruptly. At the placental implantation site, contraction and retraction of the myometrium to compress the vessels and obliterate their lumens are required to control hemorrhage. Adherent pieces of placenta or large blood clots will prevent effective myometrial contraction and retraction and thereby impair hemostasis at the implantation site. If the myometrium at and adjacent to the denuded implantation site contracts and retracts vigorously, fatal hemorrhage from the placental implantation site is unlikely even when the coagulation mechanism is severely impaired.
Some bleeding is inevitable during the third stage of labor as the result of transient partial separation of the placenta. As the placenta separates, the blood from the implantation site may escape into the vagina immediately (Duncan separation) or it may be concealed behind the placenta and membranes (Schultze separation) until the placenta is delivered. Expression of the placenta should be attempted by manual fundal pressure. Descent of the placenta is indicated by the cord becoming slack. Manual removal of the placenta is indicated when bleeding persists. The uterus should be massaged if it is not contracted firmly.
TECHNIQUE OF MANUAL REMOVAL OF PLACENTA
Adequate analgesia or anesthesia is mandatory. Aseptic surgical technique should be employed. After grasping the fundus through the abdominal wall with one hand, the other hand is introduced into the vagina and passed into the uterus, along the umbilical cord. As soon as the placenta is reached, its margin is located and the ulnar border of the hand insinuated between it and the uterine wall (Figure 28-2). Then with the back of the hand in contact with the uterus, the placenta is peeled off its uterine attachment by a motion similar to that employed in separating the leaves of a book. After its complete separation, the placenta should be grasped with the entire hand, which is then gradually withdrawn. Membranes are removed at the same time by carefully teasing them from the decidua, using ring forceps to grasp them as necessary. Some clinicians prefer to wipe out the uterine cavity with a sponge. If this is done, it is imperative that a sponge not be left in the uterus or vagina.
FIGURE 28-2 Manual removal of placenta is accomplished as the fingers are swept from side to side and advanced (A) until the placenta is completely detached, grasped, and removed (B). (Reproduced, with permission, from Cunningham FG, Leveno KJ, Bloom SL, et al (eds). Williams Obstetrics. 23rd ed. New York, NY: McGraw-Hill; 2010.)
The fundus should always be palpated following placental delivery to make certain that the uterus is well contracted. Failure of the uterus to contract following delivery is a common cause of obstetrical hemorrhage. Predisposing factors for uterine atony are shown in Table 28-1. The differentiation between bleeding from uterine atony and from lacerations is tentatively made based on the condition of the uterus. The atonic uterus is flaccid and not firm to palpation. If bleeding persists despite a firm, well-contracted uterus, the cause of the hemorrhage is most likely from lacerations. Bright red blood also suggests lacerations. To ascertain the role of lacerations as a cause of bleeding, careful inspection of the vagina, cervix, and uterus is essential.
Sometimes bleeding may be caused by both atony and trauma, especially after major operative delivery. In general, inspection of the cervix and vagina should be performed after every delivery to identify hemorrhage from lacerations. Anesthesia should be adequate to prevent discomfort during such an examination. Examination of the uterine cavity, the cervix, and the entire vagina is essential after breech extraction, after internal podalic version, and following vaginal delivery in a woman who previously underwent cesarean delivery.
If the uterus is not firm, vigorous fundal massage is indicated. Most often, 20 U of oxytocin in 1000 mL of lactated Ringer or normal saline proves effective when administered intravenously at approximately 10 mL/min (200 mU of oxytocin per minute) simultaneously with uterine massage. Oxytocin should never be given as an undiluted bolus dose as serious hypotension or cardiac arrhythmias may follow.
If oxytocin given by rapid infusion does not prove effective, some administer methylergonovine (Methergine), 0.2 mg, intramuscularly. This may stimulate the uterus to contract sufficiently to control hemorrhage. If given intravenously, methylergonovine may cause dangerous hypertension, especially in the woman with preeclampsia.
The 15-methyl derivative of prostaglandin F2α (Hemabate) may also be used for the treatment of uterine atony. The initial recommended dose is 250 μg (0.25 mg) given intramuscularly, and this is repeated if necessary at 15- to 90-minute intervals up to a maximum of eight doses. In addition to pulmonary airway and vascular constriction, side effects include diarrhea, hypertension, vomiting, fever, flushing, and tachycardia.
Bleeding Unresponsive to Oxytocics
Continued bleeding after multiple oxytocic administrations may be from unrecognized genital tract lacerations, including in some cases uterine rupture. Thus, if bleeding persists, no time should be lost in haphazard efforts to control hemorrhage, but the management detailed in Table 28-2 and Figure 28-3 should be initiated immediately. With transfusion and simultaneous manual uterine compression and intravenous oxytocin, additional measures are rarely required. Intractable atony may mandate hysterectomy as a lifesaving measure (see Chapter 20). Alternatively, uterine artery ligation (see Figure 28-4), internal iliac artery ligation, uterine compression sutures (see Figure 28-5), uterine packing, or angiographic embolization may prove successful.
TABLE 28-2. Management of Bleeding Unresponsive to Oxytocics
FIGURE 28-3 Bimanual compression of the uterus between the fist in the anterior fornix and the abdominal hand which is also used for uterine massage. This usually controls hemorrhage from uterine atony. (Reproduced, with permission, from Cunningham FG, Leveno KJ, Bloom SL, et al (eds). Williams Obstetrics. 23rd ed. New York, NY: McGraw-Hill; 2010.)
FIGURE 28-4 Uterine artery ligation. The suture goes through the lateral uterine wall anteriorly, curves around posteriorly, then reenters anteriorly. When tied, it encompasses the uterine artery. (Reproduced, with permission, from Cunningham FG, Leveno KJ, Bloom SL, et al (eds). Williams Obstetrics. 23rd ed. New York, NY: McGraw-Hill; 2010.)
FIGURE 28-5 The B-Lynch uterine compression suture technique. Parts (A), (B), and (D) demonstrate the anterior view of the uterus. Part (C) is a posterior view. Numbers denote the sequential path of the suture and are shown in more than one figure. In step 1, beginning below the incision, the needle pierces the lower uterine segment to enter the uterine cavity. In step 2, the needle exits the cavity above the incision. The suture then loops up and around the fundus to the posterior uterine surface. Here, in step 3, the needle pierces the posterior uterine wall to reenter the uterine cavity. The suture then traverses from left to right within the cavity. In step 4, the needle exits the uterine cavity through the posterior wall. From the back of the uterus, the suture loops up and around the fundus to the front of the uterus. In step 5, the needle pierces the myometrium above the incision to reenter the uterine cavity. In step 6, the needle exits below the incision. Finally, the sutures at points 1 and 6 are tied below the incision. (Reproduced, with permission, from Cunningham FG, Leveno KJ, Bloom SL, et al (eds). Williams Obstetrics. 23rd ed. New York, NY: McGraw-Hill; 2010.)
Internal Iliac Artery Ligation
Ligation of the internal iliac arteries at times reduces the hemorrhage from uterine atony appreciably (Figure 28-6). This operation is more easily performed if a midline abdominal incision is extended upward above the umbilicus. Internal iliac artery ligation reduces pulse pressure in the arteries distal to the ligation, thus turning an arterial pressure system into one with pressures approaching those in the venous circulation, which are more amenable to hemostasis via simple clot formation. Bilateral ligation of these arteries does not appear to interfere seriously with subsequent reproduction.
FIGURE 28-6 Ligation of right internal iliac artery. A. The peritoneum covering the right iliac vessels is opened and reflected. Inset: Unembalmed cadaveric dissection shows the most common location of the internal iliac vein, which lies lateral to the artery. Ideally, the ligature is placed around the anterior division of the internal iliac artery to spare tissues supplied by its posterior division. (Inset, reprinted with permission from Elsevier, Bleich AT, Rahn DD, Wieslander CK, et al: Posterior division of the internal iliac artery: Anatomic variations and clinical applications. Am J Obstet Gynecol 197(6): 658.e1–658.e5, 2007.) B. Ligation of the right internal iliac artery. A ligature is carried beneath the artery from laterally to medially with a right-angle clamp and firmly tied. (Reproduced, with permission, from Cunningham FG, Leveno KJ, Bloom SL, et al (eds). Williams Obstetrics. 23rd ed. New York, NY: McGraw-Hill; 2010.)
RETAINED PLACENTAL FRAGMENTS
Immediate postpartum hemorrhage is seldom caused by retained small placental fragments, but a remaining piece of placenta is a potential cause of bleeding later in the puerperium. Inspection of the placenta after delivery should be routine to identify missing placental fragments. If a portion of placenta is missing, the uterus should be explored and the fragment removed. Retention of a succenturiate lobe is an occasional cause of postpartum hemorrhage.
PLACENTA ACCRETA, INCRETA, AND PERCRETA
Very infrequently, the placenta is unusually adherent to the implantation site, with a scanty or absent decidua basalis and fibrinoid layer (Nitabuch layer), so that the physiological line of cleavage through the decidual spongy layer is lacking. As a consequence, one or more cotyledons are firmly bound to the defective decidua basalis or even to the myometrium. When the placenta is densely anchored in this fashion, the condition is called placenta accreta. When the villi invade the myometrium, the condition is called placenta increta; and penetration of the villi through the myometrium is termed placenta percreta (Figure 28-7). Risk factors include implantation in the lower uterine segment or implantation over a previous uterine incision.
FIGURE 28-7 Abnormally adherent placentation. A. Placenta accrete. B. Placenta increta. C. Placenta percreta. (Reproduced, with permission, from Cunningham FG, Leveno KJ, Bloom SL, et al (eds). Williams Obstetrics. 23rd ed. New York, NY: McGraw-Hill; 2010.)
The problems associated with delivery of the placenta vary appreciably, depending upon the site of implantation, depth of myometrial penetration, and number of cotyledons involved. With more extensive involvement, hemorrhage becomes profuse as delivery of the placenta is attempted. Successful treatment depends upon immediate blood replacement therapy as described in Chapter 29 and, nearly always, prompt hysterectomy. Alternative measures include uterine or internal iliac artery ligation or angiographic embolization.
INVERSION OF THE UTERUS
Complete uterine inversion after delivery of the infant is almost always the consequence of strong traction on an umbilical cord attached to a placenta implanted in the fundus (Figure 28-8). Incomplete uterine inversion may also occur (Figure 28-9). Placenta accreta may be implicated, although uterine inversion can occur without the placenta being so firmly adherent.
FIGURE 28-8 Most likely site of placental implantation in cases of uterine inversion. With traction on the cord and the placenta still attached, the likelihood of inversion is obvious.
FIGURE 28-9 A. Incomplete uterine inversion is diagnosed by abdominal palpation of the crater-like depression and vaginal palpation of the fundal wall in the lower segment and cervix. B. Progressive degrees of inversion are shown in the inset. C. To replace the uterus, the palm is placed on the center of the inverted fundus, while fingers identify the cervical margins. Upward pressure by the palm restores the uterus and elevates it past the level of the cervix. (Reproduced, with permission, from Cunningham FG, Leveno KJ, Bloom SL, et al (eds). Williams Obstetrics. 23rd ed. New York, NY: McGraw-Hill; 2010.)
Uterine inversion is most often associated with immediate life-threatening hemorrhage. Delay in treatment increases the mortality rate appreciably. Fortunately, the inverted uterus can usually be restored to its normal position by the techniques described in Table 28-3. If the uterus cannot be reinverted by vaginal manipulation, laparotomy is imperative. The fundus then may be simultaneously pushed upward from below and pulled from above. The reader is referred to Chapter 35 of Williams Obstetrics, 22nd edition, for further discussion of the surgical management of an inverted uterus.
TABLE 28-3. Treatment of Uterine Inversion
LACERATIONS AND HEMATOMAS
These lacerations usually result from injuries sustained during a forceps or vacuum operation, but they may even develop with spontaneous delivery. Such lacerations may extend deep into the underlying tissues and give rise to significant hemorrhage, which usually is controlled by appropriate suturing. They may be overlooked unless thorough inspection of the upper vagina is performed. Bleeding while the uterus is firmly contracted is strong evidence of genital tract laceration, retained placental fragments, or both.
Lacerations of the anterior vaginal wall in close proximity to the urethra are relatively common. They are often superficial with little to no bleeding, and repair is usually not indicated. If such lacerations are large enough to require extensive repair, difficulty in voiding can be anticipated and an indwelling catheter should be placed.
A deep cervical tear should always be suspected in cases of profuse hemorrhage during and after third-stage labor, particularly if the uterus is firmly contracted. Thorough examination is necessary, and the flabby cervix often makes digital examination alone unsatisfactory. Thus, the extent of the injury can be fully appreciated only after adequate exposure and visual inspection of the cervix. The best exposure is gained by the use of right-angle vaginal retractors by an assistant while the operator grasps the patulous cervix with a ring forceps (Figure 28-10).
FIGURE 28-10 Repair of cervical laceration with appropriate surgical exposure. (Reproduced, with permission, from Cunningham FG, Leveno KJ, Bloom SL, et al (eds). Williams Obstetrics. 23rd ed. New York, NY: McGraw-Hill; 2010.)
Because the hemorrhage usually comes from the upper angle of the wound, the first suture is applied just above the angle and sutured outward toward the operator. Associated vaginal lacerations may be tamponaded with gauze packs to retard hemorrhage while cervical lacerations are repaired. Either interrupted or running absorbable sutures are suitable.
Hematomas may be classified as vulvar, vulvovaginal, paravaginal, or retroperitoneal. These may develop with spontaneous or operative delivery. Occasionally, the hemorrhage is delayed. In its early stages, the hematoma forms a rounded swelling that projects into the upper portion of the vaginal canal and may almost occlude its lumen. These hematomas, particularly those that develop rapidly, may cause excruciating pain, which often is the first symptom noticed.
Smaller vulvar hematomas identified after leaving the delivery room may be treated expectantly. If, however, the pain is severe, or if the hematoma continues to enlarge, the best treatment is prompt incision. This is done at the point of maximal distention, along with evacuation of blood and clots and ligation of bleeding points. The cavity may then be obliterated with mattress sutures. Often, no sites of bleeding are identified after the hematoma has been drained. In such cases, the vagina—and not the hematoma cavity—is packed for 12 to 24 hours. With hematomas of the genital tract, blood loss is nearly always considerably more than the clinical estimate. Hypovolemia and severe anemia should be prevented by adequate blood replacement. Angiographic embolization has become popular for management of intractable hematomas.
For further reading in Williams Obstetrics, 23rd ed.,
see Chapter 35, “Obstetrical Hemorrhage.”