eMedicine Specialties > Emergency Medicine > Obstetrics & Gynecology

Pregnancy, Postpartum Hemorrhage

Author: Maame Yaa A B Yiadom, MPH, MD, Staff Physician, Department of Emergency Medicine, Brigham and Women's Hospital and Massachusetts General Hospital
Coauthor(s): Daniela Carusi, MSc, MD, Instructor, Obstetrics and Gynecology and Reproductive Biology, Harvard Medical School; Consulting Physician, Department of Obstetrics and Gynecology, Medical Director, Department of General Ambulatory Gynecology, Brigham and Women's Hospital
Contributor Information and Disclosures

Updated: Oct 21, 2009

Introduction

Background

Defining postpartum hemorrhage (PPH) is problematic and has been historically difficult. Waiting for a patient to meet the postpartum hemorrhage criteria, particularly in resource-poor settings or with sudden hemorrhage, may delay appropriate intervention. Postpartum hemorrhage is traditionally defined as blood loss greater than 500 mL during a vaginal delivery or greater than 1,000 mL with a cesarean delivery. However, significant blood loss can be well tolerated by most young healthy females, and an uncomplicated delivery often results in blood loss of more than 500 mL without any compromise of the mother's condition.

The addition of "a 10% drop in hemoglobin" to the definition provides an objective laboratory measure. However, this is not helpful in acute situations since it can take hours for losses to create laboratory changes in red blood cell measurements. Signs and symptoms of hypovolemia (lightheadedness, tachycardia, syncope, fatigue and oliguria) are also of limited utility as they can be late findings in a young and otherwise healthy female. As a result, any bleeding that has the potential to result in hemodynamic instability, if left untreated, should be considered postpartum hemorrhage and managed accordingly.

Postpartum hemorrhage can be divided into 2 types: early postpartum hemorrhage, which occurs within 24 hours of delivery, and late postpartum hemorrhage, which occurs 24 hours to 6 weeks after delivery. Most cases of postpartum hemorrhage, greater than 99%, are early postpartum hemorrhage. Notably, most women are still under the care of their delivering provider during this time. With many women delivering outside of hospitals and early postpartum hospital discharge being a growing trend, postpartum hemorrhage that presents to the emergency department may be either early or late.

Within this combined population, emergency medicine providers are likely to receive patients that fall into 1 of 3 categories:

• Those that are too close to delivery to be transferred to another location (the facility's labor and delivery suite or to another facility)
• Women who delivered at home, at a nonhospital facility, or en route to the hospital and are too hemodynamically unstable to be transferred to a labor and delivery floor within the facility or at another location
• Patients who were discharged home after delivery in stable condition, but had concerning bleeding that prompted an emergency department visit

Pathophysiology

At term, the uterus and placenta receive 500-800 mL of blood per minute through their low resistance network of vessels. This high flow predisposes a gravid uterus to significant bleeding if not well physiologically or medically controlled. By the third trimester, maternal blood volume increases by 50%, which increases the body's tolerance of blood loss during delivery.

Following delivery of the fetus, the gravid uterus is able to contract down significantly given the reduction in volume. This allows the placenta to separate from the uterine interface, exposing maternal blood vessels that interface with the placental surface. After separation and delivery of the placenta, the uterus initiates a process of contraction and retraction, shortening its fiber and kinking the supplying blood vessels, like physiologic sutures or "living ligatures."

If the uterus fails to contract, or the placenta fails to separate or deliver, then significant hemorrhage may ensue. Uterine atony, or diminished myometrial contractility, accounts for 80% of postpartum hemorrhage. The other major causes include abnormal placental attachment or retained placental tissue, laceration of tissues or blood vessels in the pelvis and genital tract, and maternal coagulopathies. An additional, though uncommon, cause is inversion of the uterus during placental delivery. 

The traditional pneumonic "4Ts: tone, tissue, trauma, and thrombosis" can be used to remember the potential causes. Here, a 5^th is added; “T” for uterine inversion that will be called “traction.” 

Frequency

United States

The incidence of postpartum hemorrhage is about 1 in 5 pregnancies, but this figure varies widely due to differential definitions for postpartum hemorrhage. 

Mortality/Morbidity

Mortality

Although accountable for only 8% of maternal deaths in developed countries, postpartum hemorrhage is the second leading single cause of maternal mortality, ranking behind preeclampsia/eclampsia.¹ Globally, postpartum hemorrhage is the leading cause of maternal mortality. The condition is responsible for 25% of delivery-associated deaths,² and this figure is as high as 60% in some countries. International initiatives to improve outcomes have invested in training birth attendants (traditional or otherwise) and nurse midwives on the active management of the third stage of labor (the period immediately after delivering of the infant). Most efforts focus on uterine atony, which is the primary cause of postpartum hemorrhage. This has included education on manual techniques to increase uterine contraction-retraction and making pharmacologic uterotonic agents (oxytocin and misoprostol) more available.^3,4,5

Morbidity

Postpartum hemorrhage is a potentially life-threatening complication of both vaginal and cesarean delivery. Associated morbidity is related to the direct consequences of blood loss as well as the potential complications of hemostatic and resuscitative interventions.

Consequences of uncontrolled hemorrhage

• Hypovolemic shock and associated organ failure including renal failure, stroke, myocardial infarction
• Postpartum hypopituitarism (Sheehan syndrome): Acute blood loss and/or hypovolemic shock during and after childbirth can lead to hypoperfusion of the pituitary and subsequent necrosis. Although often asymptomatic, it may present with an inability to breastfeed, fatigue, hypogonadism, amenorrhea, and hypotension.
• Death secondary to hypovolemic shock

Consequences of fluid resuscitation

• Fluid overload can lead to extremity edema and pulmonary edema. The latter is less common in young healthy women, but it should be suspected in the setting of large fluid and blood product resuscitation.
• Dilutional coagulopathy occurs when crystalloids and/or serum-poor blood products are given in large volume.

Risks from exposure to blood products

• Allergic or febrile reactions have an incidence of about 1 case per 333 population.⁶
• Anaphylactic reactions occur in 1 in 20,000 to 1 in 47,000 blood products transfused.⁷
• Transfusion-related acute lung injury (TRALI) occurs in 1 out of every 5,000 transfusions, but more often with high plasma containing products like fresh frozen plasma (FFP) and platelets. It often starts within 1-2 hours of the transfusion, but it can happen anytime up to 6 hours after a transfusion. The symptom complex includes severe bilateral pulmonary edema, severe hypoxemia, tachycardia, cyanosis, hypotension, and fever.⁸
• Acute immune hemolytic reaction, though rare, is the most serious type of transfusion reaction. Symptoms are associated with red blood cell hemolysis. Patients may have fevers, chills, chest and lower back pain, nausea, renal failure, and death if the transfusion is not stopped.
• Delayed hemolytic reaction: This type of reaction happens when the body slowly attacks antigens (other than ABO antigens) on the transfused blood cells. Symptoms occur days to weeks after a transfusion. Affected patients are either asymptomatic or have mild symptoms, which may include jaundice, low-grade fever, and a low hemoglobin or hematocrit.⁹
• Infection: Hepatitis is the most common disease transmitted by blood transfusions. According to the American Red Cross, about 1 blood transfusion in 205,000 transmits a hepatitis B infection, and 1 blood transfusion in about 2 million transmits hepatitis C. Other rare but potential infections include HIV (risk of 1 in 2.5 million), Lyme disease, babesiosis, and malaria. Donors are screened for potential exposure so transmission is very rare. Rarely, blood may be contaminated with tiny amounts of skin bacteria during donation. Platelets are the most likely blood product to be affected by contamination from skin flora.
• Metabolic reactions: With large volume and rapid transfusions, patients are at risk of encountering 3 metabolic reactions: hypothermia, hyperkalemia, and citrate toxicity. Hypothermia results from the transfusion of unwarmed crystalloid or colloid that drops the body temperature. Hypothermia inhibits coagulation and can worsen postpartum hemorrhage. Citrate is a blood product additive that binds serum calcium and can cause hypocalcemia with large-volume transfusions. Hemolysis occurs with red blood cell storage releasing increasing amounts of intracellular potassium with time. Transfusions of older red blood cells increase the risk of hyperkalemia.

Risks associated with surgical intervention

• Intubation and anesthesia complications: Pregnant women have an increased risk for aspiration, failed intubation, and death from failed ventilation when compared with nonpregnant patients. Respiratory injury or infection, myocardial infarction, myocardial arrhythmia, stroke, or allergic reactions to anesthetic medications may also rarely occur.
• Bleeding: Continued bleeding from the genital tract or a bleeding complication from the surgery may occur.
• Infection: Sepsis, wound infection, or pneumonia is possible.
• Deep venous thrombosis and/or pulmonary embolism: Risk is increased due to postpartum and postoperative associated hypercoagulability as well as from relative immobility in the operative and postoperative period.

Need for permanent sterilization to control bleeding

If the bleeding cannot be controlled conservatively (removal of products of conception, suturing disrupted tissues, application of pressure) then surgical intervention may be necessary. In severe cases, the following may occur:

• Hysterectomy
• Asherman syndrome, which is secondary (non-hormone mediated) amenorrhea due to uterine scarring that develops after infection and/or curettage performed to remove placental fragments

Clinical

History

The clinical history should be taken as a primary survey (ABCs) of the patient. This should include collecting an initial set of vital signs to guide the patient’s management, as the patient is positioned to begin the physical examination. Keep in mind, that if the bleeding is very brisk, the patient’s mental status may wane. As a result, this first set of questions should include queries about signs and symptoms that are most crucial in managing potential circulatory collapse, identifying the cause of postpartum hemorrhage (PPH), and selecting appropriate therapies.¹⁰

• Severity of bleeding
  • Is the placenta delivered?
  • What has been the duration of the third stage of labor?
  • How long has the bleeding been heavy?
  • Was initial postdelivery bleeding light, medium, or heavy?
  • Are symptoms of hypovolemia present such as dizziness/lightheadedness, changes in vision, palpitations, fatigue, orthostasis, syncope or presyncope?
  • If evaluating a patient with delayed postpartum hemorrhage, what has been the bleeding pattern since delivery?
• Intervention guides
  • Is there a history of transfusion? What was the reason for transfusion? Is there a history of a transfusion reaction?
  • Past medical history (particularly cardiovascular, pulmonary, or hematologic conditions)
  • Allergies
• Predisposing factors and potential etiology
  • History of postpartum hemorrhage
  • Gravity, parity, length of most recent pregnancy, history of multiple gestations
  • Number of fetuses for the most recent pregnancy
  • Pregnancy complications (polyhydramnios, infection, vaginal bleeding, placental abnormalities)
  • If the placental was delivered, was it spontaneous, or was manual delivery required?
  • Current and past history of vaginal delivery versus cesarean delivery
  • If cesarean delivery, was it planned in advance, decided upon after a failed vaginal delivery attempt, or performed emergently?
  • Other uterine surgeries such as myomectomy (transvaginal vs transabdominal), uterine septum removal
  • Personal or family history of bleeding disorder
  • Medications such as prescribed, over the counter, diet supplements, or vitamins (with particular attention to anticoagulants, platelet inhibitors, uterine relaxants, and antihypertensives)
  • Vaginal penetration since delivery (tampons, finger, other foreign object, vaginal intercourse)
  • Signs or symptoms of infection such as uterine pain or tenderness, fever, tachycardia, or foul vaginal discharge
  • Information helpful for continued management
  • When and where was the delivery?
  • Who assisted the delivery?
  • Where and with whom was prenatal care?
  • Healthy infant(s) delivered (any complications or concerns before, during, or after delivery)?
  • Past surgical history

Physical

As mentioned earlier, patients with postpartum hemorrhage (PPH) should be managed like all emergency department resuscitation situations, with the history and physical examination occurring simultaneously while following acute life support algorithms.

The physical examination should focus on determining the cause of the bleeding. The patient may not have the typical hemodynamic changes of shock early in the course of the hemorrhage due to physiologic maternal hypervolemia. 

Important organ systems to assess include the pulmonary system (evidence of pulmonary edema), the cardiovascular (heart murmur, tachycardia, strength of peripheral pulses), and neurological systems (mental status changes from hypovolemia).The skin should also be checked for petechiae or oozing from skin puncture sites, which could indicate a coagulopathy, or a mottled appearance, which can be indicative of severe hypovolemia.

Looking for occult postpartum hemorrhage—in the form of a pelvic, vaginal, uterine, or abdominal wall hematoma, or intra-abdominal or perihepatic bleeding—is always an important consideration when unstable hemodynamic findings are present without evidence of excessive vaginal blood loss. 

• Abdominal examination: Pain and tenderness (concerning for retained placenta tissue, rupture, or endometritis), distension, boggy or grossly palpable uterus (at or above the umbilicus) is suggestive of atony. Palpation of an overdistended bladder may indicate a barrier to adequate uterine contraction.
• Perineal examination: A brisk bleed should be visible at the introitus; identify any perineal lacerations.
• Speculum examination: Gently suction blood, clots, and tissue fragments as needed to maintain the view of the vagina and cervix. Careful inspection of the cervix and vagina under good light may reveal the presence and extent of lacerations.
• Bimanual examination: Bimanual palpation of the uterus may reveal bogginess, atony, uterine enlargement, or a large amount of accumulated blood. Palpation may also reveal hematomas in the vagina or pelvis. Assess if the cervical os is open or closed. 
• Placental examination: Examine the placenta for missing portions, which suggest the possibility of retained placental tissue.

Causes

The 4Ts of postpartum hemorrhage (PPH) +1: tone, trauma, tissue, thrombosis, and traction. More than one of these can cause postpartum hemorrhage in any given patient.

• Uterine atony - "Tone": Atony is by far the most common cause of postpartum hemorrhage. Uterine contraction is essential for appropriate hemostasis, and disruption of this process can lead to significant bleeding. Uterine atony is the typical cause of postpartum hemorrhage that occurs in the first 4 hours after delivery. Risk factors for atony include the following:
  • Overdistended uterus (eg, multiple gestation, fetal macrosomia, polyhydramnios)
  • Fatigued uterus (eg, augmented or prolonged labor, amnionitis, use of uterine tocolytics such as magnesium or calcium channel blockers)
  • Obstructed uterus (eg, retained placenta or fetal parts, placenta accreta, or an overly distended bladder)
• Laceration or hematoma - "Trauma": Trauma to the uterus, cervix, and/or vagina is the second most frequent cause of postpartum hemorrhage. Injury to these tissues during or after delivery can cause significant bleeding because of their increased vascularity during pregnancy. Vaginal trauma is most common with surgical or assisted vaginal deliveries. It also occurs more frequently with deliveries that involve a large fetus, manual exploration, instrumentation, a fetal hand presenting with the head, or spontaneously from friction between mucosal tissue and the fetus during delivery. Cervical lacerations are rarer now that forceps-assisted deliveries are less common. They are more likely to occur when delivery assistance is provided before the cervix is fully dilated. Risk factors for trauma include the following:
  • Delivery of a large infant
  • Any instrumentation or intrauterine manipulation (eg, forceps, vacuum, manual removal of retained placental fragments)
  • Vaginal birth after cesarean section (VBAC)
  • Episiotomy
• Retained placenta - "Tissue": Retained placental tissue is most likely to occur with a placenta that has an accessory lobe, deliveries that are extremely preterm, or variants of placenta accreta. Retained or adherent placental tissue prevents adequate contraction of the uterus allowing for increased blood loss. Risk factors for retained products of conception include the following:
  • Prior uterine surgery or procedures
  • Premature delivery
  • Difficult or prolonged placental delivery
  • Multilobed placenta
  • Signs of placental accreta by antepartum ultrasonography or MRI
• Clotting disorder - "Thrombosis": During the third stage of labor (after delivery of the fetus), hemostasis is most dependent on contraction and retraction of the myometrium. During this period, coagulation disorders are not often a contributing factor. However, hours to days after delivery, the deposition of fibrin (within the vessels in the area where the placenta adhered to the uterine wall and/or at cesarean delivery incision sites) plays a more prominent role. In this delayed period, coagulation abnormalities can cause postpartum hemorrhage alone or contribute to bleeding from other causes, most notably trauma. These abnormalities may be preexistent or acquired during pregnancy, delivery, or the postpartum period. Potential causes include the following:
  • Platelet dysfunction: Thrombocytopenia may be related to preexisting disease, such as idiopathic thrombocytopenic purpura (ITP) or, less commonly, functional platelet abnormalities. Platelet dysfunction can also be acquired secondary to HELLP syndrome (hemolysis, elevated liver enzymes, and low platelet count).
  • Inherited coagulopathy: Preexisting abnormalities of the clotting system, as factor X deficiency or familial hypofibrinogenemia
  • Use of anticoagulants: This is an iatrogenic coagulopathy from the use of heparin, enoxaparin, aspirin, or postpartum warfarin.
  • Disseminated intravascular coagulation (DIC): This can occur, such as from sepsis, placental abruption, amniotic fluid embolism, HELLP syndrome, or intrauterine fetal demise. 
  • Dilutional coagulopathy: Large blood loss, or large volume resuscitation with crystalloid and/or packed red blood cells (PRBCs), can cause a dilutional coagulopathy and worsen hemorrhage from other causes.
  • Physiologic factors: These factors may develop during the hemorrhage such as hypocalcemia, hypothermia, and acidemia.
• Uterine inversion - "Traction": The traditional teaching is that uterine inversion occurs with an atonic uterus that has not separated well from the placenta as it is being delivered, or from excessive traction on the umbilical cord while placental delivery is being assisted. Studies have yet to demonstrate the typical mechanism for uterine inversion. However, clinical vigilance for inversion, secondary to these potential causes, is generally practiced. Inversion prevents the myometrium from contracting and retracting, and it is associated with life-threatening blood losses as well as profound hypotension from vagal activation.

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