Chapter 3: Postpartum Hemorrhage

Postpartum hemorrhage is one of the most common emergencies faced by obstetricians. Not only is it a leading cause of maternal morbidity, but it remains one of the top three causes of maternal mortality throughout the world.^1,2 In order to manage postpartum hemorrhage effectively, the obstetrician must have a thorough understanding of normal delivery-related blood loss, physiologic responses to hemorrhage, the most common etiologies of postpartum hemorrhage, and appropriate therapeutic interventions.

Normal delivery-related blood loss depends on delivery mode. The average blood loss for a vaginal delivery, cesarean delivery, and cesarean hysterectomy has been estimated at 500, 1000, and 1500 mL, respectively.^{3,4, 5} These values are often underestimated and unappreciated clinically due to the significant blood volume expansion that accompanies pregnancy.

Postpartum hemorrhage has been defined in published literature.^{4,5, 6} Definitions have included subjective assessments greater than the standard norms, a 10% decline in hematocrit, and need for blood transfusion. Because of these varied definitions, the exact incidence of postpartum hemorrhage is difficult to determine; however, rough estimates suggest that postpartum hemorrhage complicates 1% to 5% of all deliveries.⁷ For practical purposes, postpartum hemorrhage is best defined as excessive bleeding that causes the patient to be hemodynamically symptomatic.

The pregnant patient is able to adapt to hemorrhage more effectively than her nonpregnant counterpart due to hemodynamic changes that accompany pregnancy. These changes include increased red cell mass, increased plasma volume, and increased cardiac output. In the early phases of hemorrhage, the body compensates by raising systemic vascular resistance in order to maintain blood pressure and perfusion to vital organs. However, as bleeding continues, further vasoconstriction is impossible resulting in drops in blood pressure, cardiac output, and end-organ perfusion.^3,8 Table 3-1 classifies the physiologic responses that occur with various stages of hemorrhage. It is important for the obstetrician to recognize these responses since the quantity of blood loss that occurs during a postpartum hemorrhage is often underestimated as stated previously.

The etiologies of postpartum hemorrhage can be categorized as primary—those occurring within 24 hours of delivery—and secondary—those occurring from 24 hours until 6 weeks after delivery.⁹ Table 3-2 lists the most common causes of primary and secondary postpartum hemorrhage. Since the obstetrician is faced with primary postpartum hemorrhage more often than secondary, the remainder of this chapter focuses on its risk factors and therapy.

Uterine Atony

Uterine atony, or the inability of the uterine myometrium to contract effectively, is the most common cause of primary postpartum hemorrhage, affecting 1 in 20 births.^9,10 At term, blood flow through the placental site averages 500 to 700 mL/min.¹ After placental delivery, the uterus controls bleeding by contracting its myometrial fibers in a tourniquet fashion around the spiral arterioles. If inadequate uterine contraction occurs, rapid blood loss will ensue.

Risk factors for uterine atony include uterine overdistention (multiple gestation, polyhydramnios, and fetal macrosomia), prolonged oxytocin use, rapid or prolonged labor, grand multiparity, chorioamnionitis, retained placental tissue, placenta previa, and use of uterine-relaxing agents (tocolytic therapy, halogenated anesthetics, nitroglycerin).¹¹

Genitourinary Tract Lacerations

The second most common cause of postpartum hemorrhage is genitourinary tract lacerations. While operative vaginal delivery remains the most significant risk factor for a genitourinary tract laceration, other sources of obstetrical trauma can contribute to this cause of hemorrhage. These sources include fetal malpresentation, fetal macrosomia, episiotomy, precipitous delivery, prior cerclage placement, Dührssen incisions, and shoulder dystocia.

A genitourinary tract laceration should be suspected if bleeding persists after a delivery despite good uterine tone. Occasionally, the bleeding may be masked due to its location, that is, broad ligament. In these circumstances, large amounts of blood loss may occur in an unrecognized hematoma. The astute obstetrician must be aware of the risk factors for this type of laceration as well as the patient’s initial presenting symptoms of pain and physiological signs of shock.

Retained Products of Conception

Retained products of conception, namely, placental tissue and amniotic membranes, can inhibit the uterus from adequate contraction and result in hemorrhage. Risk factors for retained products of conception include mid trimester delivery, chorioamnionitis, and accessory placental lobes.

Invasive Placentation

Although uncommon, invasive placentation can result in massive postpartum hemorrhage. Placenta accreta represents the abnormal attachment of the placenta to the uterine lining due to an absence of the deciduas basalis and an incomplete development of the fibrinoid layer. Placenta increta and percreta represent attachments to and through the uterine myometrium, respectively. Attempts to remove a highly invasive placenta from its attachment site will result in rapid blood loss, often necessitating emergent surgical intervention.

Major risk factors for invasive placentation include prior curettage or hysterotomy, advanced maternal age, multiparity, placenta previa, and previous cesarean delivery. As exemplified in Table 3-3, the combination of placenta previa and previous cesarean delivery should alert the physician to a substantial risk of invasive placentation and subsequent hemorrhage.¹² In these circumstances, an attempt for antepartum detection should be undertaken, and scheduled cesarean hysterectomy performed at the time of delivery if no future fertility is desired.

Uterine Rupture

Despite an uncommon incidence of 1 in 2000 deliveries, uterine rupture represents a potential catastrophic event for both mother and fetus, resulting in a significant hemorrhage if the placental implantation site is involved.¹³ While multiple risk factors have been associated with uterine rupture, no single or combination of factors is able to reliably predict all cases.^{14,15, 16} Despite this, consistent data demonstrate strong associations for trial of labor after cesarean delivery and one or more of the following: multiple prior cesarean deliveries, no previous vaginal delivery, induced or augmented labor, term gestation, thin uterine scar identified by ultrasound, multiple gestation, fetal macrosomia, postcesarean delivery infection, single layer closure of hysterotomy incision, and short interpregnancy interval.^{17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33, 34} Other risk factors include multiparity, fetal malpresentation, obstructed labor, multiple gestation, prior hysterotomy or myomectomy, uterine manipulation (eg, internal podalic version), and mid- to high-operative vaginal delivery.

Uterine Inversion

Uterine inversion, or the collapse of the fundus into the uterine cavity, is a rare event, complicating approximately 1 in 2500 deliveries.³⁵ Uterine inversion may be incomplete, complete, or prolapsed. Incomplete uterine inversion represents a partial extrusion of the fundus into the uterine cavity. With complete uterine inversion, the internal lining of the fundus crosses through the cervical os, forming a rounded mass in the vagina with no palpable fundus abdominally. Prolapsed uterine inversion refers to the entire uterus prolapsing through the cervix with the fundus passing out of the vaginal introitus. All types of uterine inversion signify a need for rapid diagnosis and correction since large volume blood loss with associated shock may ensue.

The most commonly reported cause of uterine inversion is fundal placentation with excessive cord traction in the third stage of labor.^36,37 Other associations include any clinical scenario with the potential for impaired uterine contraction after placental delivery, that is, uterine overdistention secondary to fetal macrosomia, prolonged oxytocin use, uterine malformations, and invasive placentation.

Coagulopathy

Coagulopathy represents the final major etiology of postpartum hemorrhage. Coagulopathies may be hereditary or acquired in origin. Although rare, hereditary coagulopathies may present challenging clinical courses if appropriate therapy is unavailable. In general, most of these coagulopathies are effectively treated with replacement of coagulation factors and/or additional pharmaceutical agents, that is, desmopressin (DDAVP), in the third stage of labor or at the time of cesarean delivery.

Acquired coagulopathies have numerous causes, including anticoagulant administration, sepsis, severe preeclampsia, amniotic fluid embolus, tissue necrosis (eg, retained intrauterine fetal demise and trauma), placental abruption, and consumption of clotting factors due to massive hemorrhage. Figure 3-1 reviews the pathophysiology of consumptive coagulopathy and its association with uterine atony.

When the obstetrician is faced with a postpartum hemorrhage, an organized care plan needs to be set in motion to minimize further bleeding and associated morbidity and mortality. Table 3-4 lists the components of such a care plan.

Blood Loss Needs

When faced with a postpartum hemorrhage, the first priority that a clinician should assess is his or her blood loss needs. Appropriate intravenous (IV) access is critical. This includes two large-bore (16-gauge) IV catheters. In addition, the patient’s blood type should be confirmed and held for possible cross matching needs. The patient should be provided supplemental oxygen and attempts should be made to keep the patient warm (eg, Bair Hugger warming unit). Finally, need for ancillary support should be assessed. This support may include additional nursing assistance, operating room staff, physician assistance, and an anesthesiology team.

Loss Estimation

Many instances of hemorrhage result in compounded morbidity secondary to an inadequate blood loss estimation on the part of the obstetrician. At the onset of a postpartum hemorrhage, it is important for the clinician to realistically estimate the amount of blood loss that has occurred. At this time, baseline laboratory evaluations of hemoglobin, hematocrit, platelet count, fibrinogen, prothrombin time, and partial thromboplastin time should be taken. If timely laboratory assessment is unavailable, drawing 5 mL of maternal blood into an empty red top tube and observing for clot formation will provide the clinician a rough estimate of the patient’s coagulopathy. If a clot is not visible within 6 minutes or forms and lyses within 30 minutes, the fibrinogen level is usually less than 150 mg/dL.

Etiology

After assessing blood loss needs and estimation, a rapid yet thorough exploration for the hemorrhage etiology must be undertaken. A poorly contractile uterus suggests uterine atony. If atony is not the source of bleeding, further exploration should occur. This exploration should begin with the most superior aspect of the genital tract and progress inferiorly since heavy downward blood flow may make visualization of the more inferior landmarks difficult.

Initial assessment should focus on the uterus. The most common uterine source of bleeding other than atony is retained products of conception. Figure 3-2 demonstrates proper manual exploration of the uterine cavity in order to remove retained products of conception.³⁸ Wrapping the examination hand with moist gauze can facilitate removal of retained amniotic membranes. If manual access to the uterine cavity is difficult or limited due to maternal body habitus or inadequate pain relief, transabdominal ultrasound may be used to assess for retained placental fragments. Once fragments are identified, appropriate removal may be undertaken via manual extraction and/or uterine curettage. Besides assessing for retained products of conception, a proper uterine examination can assess for evidence of invasive placentation, uterine rupture, and uterine inversion.

Once a uterine source has been excluded, attention should be focused on identifying a lower genitourinary tract laceration. Cervical and/or vaginal fornix lacerations are often difficult to repair due to their location. In these situations, it is best to have early assistance for retraction in order to visualize the laceration and provide adequate repair. In some instances, moving to an operating room to provide more adequate pain relief, pelvic relaxation, and visualization will save time and subsequent bleeding since a proper repair can be instituted more efficiently. In addition, lacerations that involve sites near the urethra and/or bowel may be challenging from the technical as well as visual perspectives. In these circumstances, employing additional instrumentation (eg, transurethral catheter) may protect uninjured entities and allow for a better repair.

After the most common etiologies of postpartum hemorrhage are excluded, other sources of bleeding should be assessed. Being aware of the risk factors for these etiologies will decrease diagnostic time and allow for more timely intervention.

Estimated Blood Loss Replacement

Understanding the patient’s requirements for fluid and blood component therapy is critical to providing adequate care to the bleeding patient. Estimated blood loss (EBL) replacement begins with appropriate fluid resuscitation. Warmed crystalloid solution in a 3:1 ratio to EBL will provide the initial volume necessary to stabilize a bleeding patient. Once appropriate volume resuscitation has occurred, additional blood component therapy may be tailored to the individual patient’s needs and blood loss. It is important for the clinician to understand the expected clinical response to the blood product therapy that is given (see Chap. 2).

In the past, there was no consensus regarding optimal blood product replacement. However, newer data from military experience suggest improved outcomes when the ratio of packed red blood cells (PRBCs) to fresh frozen plasma (FFP) to platelets is 1:1:1.^{39,40,41,42,43, 44} In addition, hospital-based massive transfusion protocols have been successful in consumptive coagulopathy management due to postpartum hemorrhage. Stanford University Medical Center has incorporated a fixed protocol of 6:4:1 for PRBC to FFP to apheresed platelets.⁴⁵ Other centers have added 6 to 10 units of thawed cryoprecipitate to this regimen.⁴⁶

Drug Therapy

Uterotonic medications represent the mainstay of drug therapy for postpartum hemorrhage due to uterine atony. Table 3-5 lists available uterotonic agents, their dosage, side effects, response time, and contraindications.^46,47

When atony is due to tocolytic therapy that impairs calcium entry into the cell (magnesium sulfate, nifedipine), an additional agent to employ is calcium. Given as an intravenous push, one ampule of calcium chloride or calcium gluconate can effectively improve uterine tone and minimize bleeding due to atony.

Intraoperative Management

Intraoperative management encompasses simple conservative techniques to hysterectomy. The main objective that a clinician must keep in mind when embarking upon an operative course is to proceed efficiently with those techniques that he or she finds easy, and avoid those that are either technically difficult or excessively time consuming.

Along with concurrent drug therapy, uterine atony should initially be managed with gentle bimanual massage. Figure 3-3 demonstrates the proper technique for bimanual massage.³⁸ Care must be taken to avoid aggressive massage that can injure the large vessels of the broad ligament.

If retained products of conception are the cause of postpartum hemorrhage and manual extraction is unsuccessful, uterine curettage should be undertaken. While this may be performed in a delivery room, excessive bleeding mandates that an operating room be used for the procedure. Not only does moving the patient to the operating room remove potential distractions for efficient therapy, but it also allows for improved visualization, patient relaxation, ancillary support, and further operative management if the curettage is unsuccessful. A large Banjo (blunt) curette should be employed with gentle traction in order to avoid uterine perforation. Transabdominal ultrasound guidance may be helpful in assisting the clinician with removal of retained placental fragments.

If uterine inversion is the source of bleeding, rapid replacement of the uterus to its proper orientation will resolve the hemorrhage. This is best accomplished in an operating room with the assistance of an anesthesiologist. The uterus and cervix should be initially relaxed with a tocolytic agent (eg, magnesium sulfate, terbutaline), nitroglycerin, or a halogenated anesthetic. Once adequate relaxation is accomplished, gentle pressure should be applied to the uterine fundus in order to revert it back into its proper abdominal location. Once the uterus has been replaced, uterotonic therapy should be given to assist with uterine contraction and prevent future inversion. On rare occasions, this conservative approach for uterine repositioning is unsuccessful and alternative therapy with hydrostatic reduction and/or surgical repair by laparotomy must be performed.

Tamponade techniques are conservative approaches that may avoid further surgery or treat surface bleeding while EBL replacement is underway. A variety of techniques are available, including packing and balloon devices. Packing typically entails the use of continuous gauze (eg, Kerlix) within a sterile plastic bag or impregnated with thrombin 5000 units in 5 mL.⁴⁶ The pack is left in place for approximately 12 to 24 hours while close attention is paid to the patient’s vital signs, laboratory parameters, and urine output. Transurethral Foley catheter placement and prophylactic antibiotic use should be considered to prevent urinary retention and infection, respectively.

Several balloon devices are available for uterine tamponade, including the Bakri tamponade balloon, BT-Cath, and the Glenveigh Ebb complete tamponade system. Tamponade balloons can be used in isolation for postpartum hemorrhage control or in conjunction with other procedures (ie, surgery or selective arterial embolization). The Bakri tamponade balloon (Cook Urological, Bloomington, Indiana) is placed within the uterus either manually or under ultrasound guidance (Fig. 3-4). Once properly located, the balloon is filled with saline until bleeding stops. The balloon can hold 500 mL of saline and withstand a pressure of 300 mm Hg. Surveillance of persistent bleeding is possible as the balloon catheter drains into a collection bag. After bleeding has slowed, the balloon can be gradually deflated and subsequently removed. The BT-Cath is similar to the Bakri balloon in that it is a silicone device with a double lumen catheter for saline filling and uterine drainage; however, it is shaped like an inverted pear. The Glenveigh Ebb complete tamponade system incorporates both intrauterine and intravaginal tamponade (Fig. 3-5).³⁸ Both balloons are made of strong yet malleable polyurethane, allowing for better conformation to the uterine and vaginal shapes. In addition, the uterine balloon can be rapidly inflated from a saline bag to a larger volume of 750 mL for circumstances in which the smaller balloons are inadequate (multiple gestations). Finally, like the other balloons, this system has a drainage port to assess for ongoing bleeding; however, unlike the others, it also has an infusion port to irrigate the uterus.

When bleeding continues despite conservative therapy, surgical management via laparotomy must be considered. Interventions include arterial ligation, uterine compression sutures, and hysterectomy.

The goal of arterial ligation is to decrease uterine perfusion and subsequent bleeding. Success rates have varied from 40% to 95% in published literature depending upon which arteries are ligated.^{47,48,49,50, 51} Arterial ligation may be performed on the uterine, utero-ovarian (Fig. 3-6), and hypogastric arteries. Hypogastric artery ligation can be technically challenging and is not recommended unless the obstetrician is extremely skilled in performing the procedure. Bakri has described a bilateral looped uterine suture technique that compresses the uterine vessels against the entire thickness of the lateral uterine wall (Fig. 3-7). It is recommended that a tamponade balloon be placed with the suture placement to ensure adequate hemorrhage control.⁵²

Uterine compression sutures are simple, effective techniques to reduce bleeding and avoid hysterectomy. Several techniques have evolved over the past 15 years, including the B-Lynch suture, Hayman vertical sutures, Pereira transverse and vertical sutures, and multiple square sutures.^{53,54,55,56,57, 58} Figures 3-8,3-9,3-10, 3-11 demonstrate these techniques. Compression sutures are best used for cases of uterine atony controlled by bimanual massage and focal invasive placentation with desire for future fertility.

Hysterectomy provides definitive therapy in cases of refractory bleeding. Since blood flow may be torrential, it is prudent for the clinician to consider performing a supracervical hysterectomy in some situations. This is especially important when the patient is unstable. Also, assistance from other surgical specialties may be necessary and a delay in consultation should be avoided.

Nonobstetrical Services

Nonobstetrical services that are particularly useful in postpartum hemorrhage management include interventional radiology, the pharmacy, and an intensive care team. Selective arterial embolization has gained success and popularity for postpartum hemorrhage management. The technique involves pelvic angiography to visualize the bleeding vessels and placement of Gelfoam (gelatin) pledgets into the vessels for occlusion. Reported success rates approximate 90% to 95%.^{59,60,61, 62} Advantages to embolization include selectivity, uterine/fertility preservation, minimal morbidity, and ability to forego or delay surgical intervention. Reported disadvantages include postembolization fever, infection, ischemic pain, and tissue necrosis. Unfortunately, a lack of rapid availability may limit its usefulness in some facilities.

In addition to interventional radiology, another nonobstetrical service that may be critical in successful postpartum hemorrhage management is the pharmacy. Recombinant activated factor VIIa, RiaSTAP, and hemostatic agents can be extremely effective pharmaceutical agents in postpartum hemorrhage management. Recombinant activated factor VIIa is given as an intravenous bolus over a few minutes in average doses of 60 to 100 μg/kg.^{63,64,65,66,67,68, 69} In conjunction with other blood component therapy, recombinant activated factor VIIa can achieve rapid hemostasis within 10 to 40 minutes. Unfortunately, the half-life of the agent is relatively short (2 hours) so repeated dosing may be necessary in some cases.^{67,68, 69}

Besides recombinant activated factor VIIa, another promising pharmaceutical agent for coagulopathy management is RiaSTAP, or fibrinogen concentrate. RiaSTAP is an intravenous therapy of fibrinogen made from human plasma. Recently approved by the Food and Drug Administration (FDA), RiaSTAP has been successfully used in Europe for the treatment of massive hemorrhage due to consumptive coagulopathy (trauma, surgery, gastrointestinal hemorrhage) and congenital fibrinogen deficiency.⁷⁰

Hemostatic agents include fibrin sealants (eg, Tisseal), topical thrombin (eg, Thrombogen and CoStasis), hemostatic matrices (eg, Floseal), gelatin sponges (eg, Gelfoam), oxidized regenerated cellulose (eg, Surgicel), and microfibrillar collagen, (eg, Avitene).⁷¹ While each of these agents has different clotting factors and mechanisms of action, they are all effective either singly or in combination for control of bleeding surfaces. These agents are particularly helpful in situations of consumptive coagulopathy associated with diffuse low-volume bleeding.

A final nonobstetrical service line to consider is an intensive care team. The patient who endures a severe postpartum hemorrhage is at risk of multiple comorbidities as noted in the following section. These comorbidities can often be avoided or dealt more efficiently with the assistance of an intensive care team that is accustomed to the hemodynamic challenges of massive hemorrhage and transfusion.

General Complication Assessment

Once a postpartum hemorrhage has successfully been treated, the patient is still at risk for complications related to the blood loss, the therapy, or both. It is important for the obstetrician to critically assess the patient for general organ system complications. These complications include hypoperfusion injuries to the brain, heart, and kidneys; infection; persistent coagulopathy; acute lung injury due to massive transfusion requirements; and pituitary necrosis. By being aware of these potential complications, the physician can ensure that proper posthemorrhage care and consultation are available in a timely fashion so that further morbidity can be avoided.