Postpartum Hemorrhage The Department of OB/GYn of Xinjiang Medical University Definition Postpartum hemorrhage denotes excessive bleeding (>500mL in vaginal delivery) following delivery. Hemorrhage may occur before, during, or after delivery of the placenta. Actual measured blood loss during uncomplicated vaginal deliveries has been shown to average 700mL, and blood loss may often be underestimated. Nevertheless, the criterion of a loss of 500mL is acceptable on historical grounds and because 1 unit (U) of blood also contains 500Ml. The parallel has obvious value in estimating the need for transfusion. Blood lost during the first 24 hours after delivery is early postpartum hemorrhage; Blood lost between 24 hours and 6 weeks after delivery is late postpartum hemorrhage. Incidence The incidence of excessive blood loss following vaginal delivery is 5-8%. Postpartum hemorrhage is the most common cause of excessive blood loss in pregnancy, and most transfusions in pregnant women are performed to replace blood lost after delivery. Hemorrhage in the third leading cause of maternal mortality in the USA and is directly responsible for about one-sixth of maternal deaths. In less –developed countries, hemorrhage is among the leading obstetric causes of maternal deaths. Morbidity & Mortality Although any woman may suffer excessive blood loss during delivery, women already compromised by anemia of intercurrent illness are more likely to demonstrate serious deterioration of condition, and anemia and excessive blood loss may predispose to subsequent puerperal infection. Major morbidity associated with transfusion therapy (e.g, hepatitis, human immunodeficiency virus infection, transfusion reactions) is infrequent but it is not insignificant. Moreover, other types of treatment for anemia may involve some risk. Postpartum hypotension may lead to partial or total necrosis of the anterior pituitary gland and cause postpartum panhypopituitarism, or Sheehan’s syndrome, which is characterized breast size, loss of pubic and axillary hair, hypothyroidism, and adrenal insufficiency. The condition is rare (<1 in 10.000 deliveries). A woman who has been hypotensive postpartum and who is actively lactating probably does not have Sheehan’s syndrome. Hypotension can also lead to acute renal failure and other organ system injury. In extreme hemorrhage, sterility will result from hysterectomy performed to control intractable postpartum hemorrhage. Etilolgy Causes of postpartum hemorrhage include uterine atony, obstetric lacertations, retained placental tissue, and coagulation defects. A. Uterine Atony Postpartum bleeding is physiologically controlled by constriction of interlacing myometrial fibers that surround the blood vessels supplying the placental implantation site. Uterine atony exists when the myometrium cannot contract. Atony is the most common cause of postpartum hemorrhage (50% of cases). Predisposing causes include Excessive manipulation of the uterus, General anesthesia (particularly with halogenated compounds), Uterine overdistention (twins or polyhydramnios), Prolonged labor, Grand multiparity, Uterine leiomayomas, Operative delivery and intrauterine manipulation, Oxytocin induction or augmentation of labor, Previous hemorrhage in the third stage Uterine infection, Extavasation of blood into the myometrium (Couvelaire uterus), And intrinsic myometrial dysfunction. B. obstetric Lacerations Excessive bleeding from an episiotomy, lacerations, or both cause about 20% of postpartum hemorrhages. Lacerations can involve the uterus, cervix, vagina, or vulva, and they usually result from precipitate or uncontrolled delivery or operative delivery of a large infant. However, they may occur after any delivery. Laceration of blood vessels underneath the vaginal or vulvar epithelium results in hematomas. Bleeding is concealed and can be particularly dangerous, since it may go unrecognized for several hours and only become apparent when shock occurs. Episiotomies may cause excessive bleeding if they involve arteries or large varicosities, if the episiotomy is large, if there is a delay between episiotomy and delivery, or if there is a delay between delivery and repair of the episiotomy . Persistent bleeding (especially bright red) and a well-contracted, firm uterus suggest bleeding from a laceration or from the episiotomy. When cervical or vaginal lacerations are identified as the source of postpartum hemorrhage, repair is best performed with adequate anesthesia. Spontaneous rupture of the uterus is rare. Risk factors for this complication include grand multiparity, malpresentation, previous uterine surgery, and oxytocin induction of labor. Rupture of a previous cesarean section scar after vaginal delivery may be an increasingly important cause of postpartum hemorrhage. C. Retained Placental Tissue Retained placental tissue and membranes cause 5-10% of postpartum hemorrhages Retention of placental tissue in the uterine cavity occurs in placenta accrete, in manual removal of the placenta, in mismanagement of the third stage of labor, and in unrecognized succenturiate placenta. Ultrasound and transvaginal duplex Doppler imaging are effective in evaluating these patients. These noninvasive methods of evaluation can identify retained blood clots or placental tissue. If the endometrial cavity appears empty, unnecessary dilataion and curettage may be avoided. D. Coagulation Defects Coagulopathies in pregnancy may be acquired coagulation defects seen in association with several obstetric disorders, including abruption placentae, excess thromboplastin from a retained dead fetus, amniotic fluid embolism, severe preeclampsia, eclampsia, and sepsis. These coagulopathies may present as hypofibrinogenemia, thrombocytopenia, and disseminated intravascular coagulation. Transfusion of more than 8 IU of blood may in itself induce a dilutional coagulopathy. Von Willebrand’s disease, autoimmune thrombocytopenia, and leukemia may also occur in pregnant women. Risk Factors Prevention of hemorrhage is preferable to even the best treatment. All patients in labor should be evaluated for risk of postpartum hemorrhage. Risk factors include: coagulopathy, hemorrhage, or blood transfusion during a previous pregnancy; anemia during labor; grand multiparity; multiple gestation; large infant; polyhydramnios; dysfunctional labor; oxytocin induction or augmentation of labor; rapid or tumultuous labor; severe preeclampsia or eclampsia; vaginal delivery after previous cesarean birth; general anesthesia for delivery; and midforceps delivery. Management A. Predelivery Preparation: All obstetric patients should have blood typed and screened on admission. Patients identified as being at risk for postpartum hemorrhage should have their blood typed and cross-matched immediately. The blood should be reserved in the blood band for 24 hours after delivery. A large-bore intravenous catheter should be securely taped into place after insertion. Delivery room personnel should be alerted to the risk of hemorrhage. Severely anemic patients should be transfused as soon as cross-matched blood is ready. With increasing concerns associated with blood transfusion, autologous blood domation in obstetric patients at risk for postpartum hemorrhage has been advocated. B. Delivery Following delivery of the infant, the uterus is massaged in a circular or back-and –forth motion until the myometrium becomes firm and well contracted. Excessive and vigorous massage of the uterus before, during, or after delivery of the placenta may interfere with normal contraction of the myometrium and instead of hastening contraction may lead to excessive postpartum blood loss. C. Third Stage of Labor Normal Placental Separation The placenta typically separates from the uterus and is delivered within 5 minutes of delivery of the infant. Attempts to speed separation are of no benefit and may cause harm. Spontaneous placental separation is impending if the uterus becomes round and firm, a sudden gush of blood comes from the vagina, the uterus seems to rise in the abdomen, and the umbilical cord moves down out of the vagina. The placenta can then be removed from the vagina by gentle traction on the umbilical cord. Prior to placental separation, gentle steady traction on the cord combined with upward pressure on the lower uterine segment (Brandt-Andrews maneuver) ensures that the placenta can be removed as soon as separation occurs and provides a means of monitoring the consistency of the uterus. Adherent membranes can be removed by gentle traction with ring forceps. The placenta is inspected for completeness immediately after delivery. Manual Removal of the Placenta Opinion is divided about the timing of manual removal of the placenta. In the presence of hemorrhage, it is obviously unreasonable to wait for spontaneous separation, and manual removal of the placenta should be undertaken without delay. Efforts to promote routine manual removal of the placenta were often made in the past. The rationale includes shortening the third stage of labor, decreasing blood loss, developing experience in placenta accrete, and providing a way to simultaneously explore the uterus. These real or potential benefits must be weighed against the discomfort caused to the patient, the risk of infection, and the risk of causing more bleeding by interfering with normal mechanisms of placental separation. Technique The uterus is stabilized by grasping the fundus with a hand placed over the abdomen. The other hand traces the course of the umbilical cord through the vagina and cervix into the uterus to palpate the edge of the placenta. The membranes at the placental margin are perforated, and the hand is inserted between the placenta and the uterine wall, palmar side toward the placenta. The hand is then gently swept from side to side and up and sown to peel the placenta from its attachments to the uterus. When the placenta has been completely separated from the uterus it is grasped and pulled from the uterus. The fetal and maternal sides of the placenta should be inspected to ensure that it has been removed in its entirety. On the fetal surface, incomplete placental removal is manifested as interruption of the vessels on the chorionic plate, usually shown by hemorrhage. On the maternal surface, it is possible to see where cotyledons have been detached. If there is evidence of incomplete removal, the uterus must be re-explored and any small pieces of adherent placenta removed. The uterus should be massaged until a firm myometrial tone is achieved. Immediate Postpartum Period Uterotonic agents may be administered as soon as the infant’s anterior shoulders is delivered, but this risks entrapment of the placenta or of an undiagnosed second twin inside a tightly contracted uterus. Routine administration of oxytocics during the third stage reduces the blood loss of delivery and decreases the chances of postpartum hemorrhage by 40% (Elbourne et al, 1998). Oxytocin, 10-20U/L of isotonic saline, or other intravenous solution by slow intravenous infusion, or 10U intramuscularly, can be used in every patient after delivery of the infant. Repair of Lacerations If bleeding is excessive before placental separation, manual removal of the placental is indicated. Otherwise, excessive manipulation of the uterus should be avoided. The vagina and cervix should be carefully inspected immediately after delivery of the placenta, with adequate lighting and assistants available. The episiotomy is quickly repaired after massage has produced a firm, tightly contracted uterus. A pack placed in the vagina above the episiotomy helps to keep the field dry; attaching the free end of the pack to the adjacent drapes reminds the operator to remove it after the repair is completed. The tendency of bleeding vessels to retract from the laceration site is the reason for one of the cardinal principles of repair. Begin the repair above the highest extent of the laceration. The highest suture is also used to provide gentle traction to bring the laceration site closer to the introitus. Hemostatic ligatures are then placed in the usual manner, and the entire birth canal is carefully inspected to make sure that there are no additional bleeding sites. Extensive inspection also provides time to confirm that prior hemostatic efforts have been effective. A cervical or vaginal laceration extending into the broad ligament should not be repaired vaginally. Laparotomy with evacuation of the resultant hematoma and hemostatic repair or hysterectomy is required. Large or expanding hematomas of the vaginal walls require operative management for proper control. The vaginal wall is first exposed by an assistant. If a laceration accompanies the hematoma, the laceration is extended so that the hematoma can be completely evacuated and explored. When the bleeding site is identified, a large himostatic ligature can be placed well above the site. This ensures hemostasis in the vessel, which is likely to retract when lacerated. The hematoma cavity should be left open to allow drainage of blood and ensure that bleeding will not be concealed if hemostasis cannot be achieved. If there is no laceration in the vaginal side wall when a hematoma is identified, then an incision must be made over the hematoma to allow treatment to proceed as outlined above. Following delivery, recovery room attendants should frequently massage the uterus and check for vaginal bleeding. Evaluation of Persistent Bleeding If vaginal bleeding persists after delivery of the placenta, aggressive treatment should be initiated. It is not sufficient to perform perfunctory uterine massage, for instance, without searching for the cause of the bleeding and initiating definitive treatment. The following steps should be undertaken without delay: Manually compress the uterus Obtain assistance. If not already done, obtain blood for typing and cross-matching. Observe blood for clotting to rule out coagulopathy. Begin fluid or blood replacement. Carefully explore the uterine cavity. Completely inspect the cervix and vagina. Insert a second intravenous catheter for administration of blood or fluids. Measures to Control Bleeding Manual exploration of the uterus The uterus should be explored immediately in women with postpartum hemorrhage. Manual exploration should also be considered after delivery of the placenta in the following circumstances: (1) when vaginal delivery follows previous cesarean section; (2) when intrauterine manipulation, eg, version and extraction, has been performed; (3) when malpresentation has occurred during labor and delivery; (4) when a premature infant has been delivered; (5) when an abnormal uterine contour has been noted prior to delivery; and (6) when there is a possibility of undiagnosed multiple pregnancy-to rule out twins. Ensure that all placental parts have been delivered and that the uterus is intact. This should be done even in the case of a well-contracted uterus. Exploration performed for reasons other than the evaluation of hemorrhage should also confirm that the uterine wall is intact and should attempt to identify any possible intrauterine structural abnormalities. Technique Place a fresh glove over the glove on the exploring hand. Form the hand into a cone and gently introduce it by firm pressure through the cervix while the fundus is stabilized with the other hand. Sweep the backs of the first and second fingers across the entire surface of the uterus, beginning at the fundus. In the lower uterine segment, palpate the walls with the palmar surface of one finger. Uterine lacerations will be felt as an obvious anatomic defect. All exploration should be gentle, since the postpartum uterus is easily perforated. Uterine rupture detected by manual exploration in the presence of postpartum hemorrhage requires immediate laparotomy. A decision to repair the defect or proceed with hysterectomy is made on the basis of the extent of the rupture, the patient’s desire for future childbearing, and the degree of the patient’s clinical deterioration. Bimanual compression and massage The most important step in controlling atonic postpartum hemorrhage is immediate bimanual uterine compression, which may have to be continued for 20- 30 minutes or more. Fluid replacement should begin as soon as a secure intravenous line is in place. Typed and cross-matched blood is given when it is available. Manual compression of the uterus will control virtually all cases of hemorrhage due to uterine atony, retained products of hemorrhage due to uterine atony, retained products of conception, and coagulopathies, and it may even control bleeding from a lacerated cervix.
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