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303
1. What is a low-lying placenta?
When the edge of the placenta is less than 2 cm from the internal cervical os but does not cover it.
In general, women can still be delivered vaginally without an increased risk of complication if the
placenta is at least 1 cm from the internal os.
2. What is a placenta previa?
Placenta previa is a condition in which placental tissue abuts or overlies the internal cervical os.
3. To what does the term “placental migration” refer?
Placental migration is a term used to explain the common occurrence of placenta previa diagnosed
early in pregnancy that resolves by the late third trimester. Two hypotheses have been proposed for
this phenomenon. First, the development of the lower uterine segment at later gestations increases
the distance between the lower placental edge and the internal os. Second, trophotropism results in
the preferential growth of trophoblastic tissue in more vascularized areas of the uterus, which is in the
direction toward the fundus (i.e., away from the cervix).
4. Why does placenta previa cause bleeding?
Physiologic changes in the cervix and lower uterine segment, as well as contractions, can produce
shearing forces at the inelastic placental attachment site. Vaginal examination or coitus can also dis-
rupt the intervillous space and cause bleeding (placental location should always be verified to ensure
that there is no placenta previa before a digital cervical check is performed). Bleeding is primarily
maternal, but fetal bleeding can occur if a fetal vessel is disrupted.
5. What is the incidence of placenta previa at term, and in the second trimester?
The overall reported incidence of placenta previa at delivery is 4 in 1000. In the second trimester,
placenta previa may be found in 4% to 6% of pregnancies.
6. What are the common risk factors for placenta previa?
• Multifetal gestation
• Increasing parity and maternal age
• Previous cesarean delivery
• Previous placenta previa
• Previous intrauterine surgical procedure (e.g., curettage)
• Cigarette smoking
7. What role does cigarette smoking play in the risk of placenta previa?
Cigarette smoking increases the risk of placenta previa at least twofold. The reason is thought to be
chronic carbon monoxide hypoxemia causing compensatory placental hypertrophy that covers a larger
surface area.
8. What other obstetric complications are associated with placenta previa?
• Preterm labor and rupture of membranes
• Fetal malpresentation
• Intrauterine growth restriction
• Congenital anomalies
• Placenta accreta, increta, or percreta
9. What are maternal complications of placenta previa?
Maternal complications include hemorrhage, uterine atony, and increased risk of blood transfusions. If
bleeding cannot be controlled, postpartum hysterectomy or pelvic artery embolization may be required.
CHAPTER 66
PLACENTA PREVIA AND
PLACENTAL ABRUPTION
Christine Djapri, MD
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304 LABOR, DELIVERY, AND POSTPARTUM
10. What are potential fetal complications of placenta previa?
Potential fetal complications include poor growth, morbidity related to preterm delivery, hypoxia, and
neonatal demise.
11. How is placenta previa diagnosed?
Ultrasound examination is the mainstay of diagnosis and should be used to exclude placenta previa
in any woman beyond 20 weeks of gestation who presents with vaginal bleeding before any digital
pelvic examination is performed. For this purpose, transvaginal ultrasound and translabial ultrasound
are both more sensitive than transabdominal ultrasound. Magnetic resonance imaging (MRI) is usually
reserved for complicated cases in which placenta accreta is suspected (see later).
12. How does placenta previa manifest?
In the majority of cases, no symptoms are present, and the diagnosis is made at the time of a routine
ultrasound examination. If women become symptomatic, the characteristic clinical presentation is
painless vaginal bleeding. Some women (10% to 20%) present with both bleeding and uterine con-
tractions. The amount of bleeding can vary from light spotting to overt hemorrhage.
13. How is placenta previa managed?
Management of placenta previa depends on the clinical situation, although all deliveries of a living
fetus are performed by cesarean section.
• Asymptomatic women are followed with ultrasound examinations to assess placental location and fe-
tal growth. To avoid labor and peripartum hemorrhage, delivery is scheduled between 36 and 37 weeks
of gestation. Cervical examinations and sexual intercourse should be avoided throughout the pregnancy.
• Women with vaginal bleeding: Maternal hemodynamic stability should be closely monitored, and
continuous fetal monitoring with tocometry (assess for contractions) should be performed in all vi-
able pregnancies. Laboratory tests that should be performed immediately include a complete blood
count, coagulation studies (fibrinogen level, activated partial thromboplastin time, prothrombin
time, and D-dimer), and a Kleihauer-Betke test to check for fetal bleeding. A large-bore intrave-
nous access should be secured and intravenous fluids administered as needed. Patients should
be crossmatched for blood and transfused as needed. Nonreassuring fetal status and refractory
maternal hemorrhage are indications for delivery.
Other considerations:
• Tocolysis can be given if vaginal bleeding is accompanied by uterine contractions.
• For patients who are at 24 to 32 weeks of gestation and delivery is likely to occur within the next
24 hours, magnesium sulfate can be administered for fetal neuroprotection.
• Antenatal corticosteroids should be administered to patients between 24 and 34 weeks of gestation
to enhance fetal pulmonary maturity.
• Rh(D) immune globulin should be given to all Rh-negative, unsensitized women who experience bleeding.
14. In which cases of placenta previa is a classic uterine incision preferred over a low
transverse incision?
To avoid cutting through the placenta, an anterior placenta previa is best managed with a low vertical
or classical uterine incision. With posterior, central, or lateral placenta previa, a low transverse incision
can often be used, provided the lower uterine segment is sufficiently developed (i.e., the fetus is not
severely preterm).
15. What is the risk of recurrence for placenta previa?
Placenta previa recurs in 4% to 8% of subsequent pregnancies.
16. What is vasa previa?
When fetal blood vessels are positioned over the internal os. Vasa previa is usually associated with
a velamentous cord insertion or a succenturiate lobe (see Chapter 34). If these vessels rupture, fetal
exsanguination and death can occur.
17. What is placenta accreta?
Placenta accreta is a condition in which trophoblastic invasion occurs past the Nitabuch layer (a fibri-
noid zone where the trophoblasts normally meets the decidua basalis). Placental detachment does not
readily occur at the time of delivery, and massive hemorrhage can ensue. This condition is considered
life-threatening to the mother and should be followed by experts. When the placenta invades into the
myometrium, the term placenta increta is used. Invasion past the uterine serosa into adjoining pelvic
structures (bladder, bowel, and/or vessels) is called placenta percreta.
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PLACENTA PREVIA AND PLACENTAL ABRUPTION 305
18. What is the association between placenta previa and placenta accreta?
Although placenta accreta can occur in the absence of placenta previa, the presence of placenta
previa increases the risk of abnormal placental invasion. The risk of having a placenta accreta in
the presence of a placenta previa is 1% to 5%; this increases to 25% with a history of one previous
cesarean delivery and to 45% with two or more.
19. What are risk factors for placenta accreta?
• Advanced maternal age (≥35 years of age)
• Multiparity
• Placenta previa
• Previous cesarean section (higher risk when combined with placenta previa)
20. What is placental abruption?
Detachment of the placenta from its implantation site before delivery of the fetus. The three predomi-
nant locations are subchorionic (between the placenta and membranes), retroplacental (between the
placenta and myometrium), and preplacental (between the placenta and amniotic fluid). Retroplacental
hematomas are associated with the worst prognosis for fetal survival.
21. What is chronic placental abruption?
Abruption that occurs early in pregnancy but is not severe enough to result in immediate fetal demise.
It is often associated with maternal hypertension and ischemic placental disease.
22. What is the incidence of placental abruption?
The overall incidence of placental abruption ranges from 0.4% to 1% of pregnancies.
23. What are common risk factors for placental abruption?
• Maternal hypertensive disorders, including preeclampsia
• Preterm premature rupture of membranes
• Rapid uterine decompression associated with multiple gestations and polyhydramnios
• Cigarette smoking
• Cocaine abuse
• Previous history of placental abruption
• Trauma
24. How does placental abruption manifest?
Fetal distress and acute abdominal or back pain are common, as well as vaginal bleeding. Uterine
tenderness or rigidity can also occur. Ten percent to 20% of all abruptions are concealed and do not
cause vaginal bleeding; in these cases, the blood is retained between the detached placenta and the
uterus (Fig. 66-1, A).
25. What are other potential causes of bleeding in the third trimester?
• Placenta previa
• Vasa previa
• Placental abruption
• Early labor (bloody show)
• Lesions of the lower genital tract (e.g., herpes, cervical cancer)
• Vaginal trauma or foreign bodies
26. Is the bleeding associated with an abruption maternal or fetal in origin?
Similar to placenta previa, bleeding associated with an abruption is mostly maternal. Significant fetal
bleeding is much more likely in cases associated with trauma.
KEY POINTS: PLACENTA PREVIA
1. The overall incidence of placenta previa in the second trimester (4%) is 10-fold more than
the incidence of placenta previa at term (0.4%).
2. Placenta previa is diagnosed with ultrasound examination. Digital pelvic examination is
contraindicated.
3. Placenta previa classically manifests as painless third trimester vaginal bleeding; management
depends on the severity as well as on maternal and fetal status.
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306 LABOR, DELIVERY, AND POSTPARTUM
27. How is the diagnosis of placental abruption made?
The diagnosis is usually clinical; the classic triad is vaginal bleeding, abdominal or back pain, and
nonreassuring fetal status or fetal demise. Some, but not all, abruptions can be seen with ultrasound;
it should not be the sole method used to eliminate this disorder from a differential diagnosis.
28. What are maternal complications of placental abruption?
Potential maternal complications include excessive blood loss resulting in hypovolemic shock, end-
organ damage (especially renal), need for blood transfusion, and death. Another major complication is
disseminated intravascular coagulation (DIC), which is most likely to occur in cases severe enough to
cause fetal death or massive hemorrhage. DIC is thought to result from entry of thromboplastins into
the circulation from the site of placental injury that results in intravascular activation of the clotting
cascade.
29. What are the potential fetal complications of placental abruption?
The most significant fetal complications are morbidity associated with preterm delivery, hypoxemia,
and death. A higher incidence of cerebral palsy has been seen in survivors of placental abruption. In
cases of chronic abruption, complications include intrauterine growth restriction and oligohydramnios.
30. How should placental abruption be managed?
Management depends on severity, gestational age, and maternal-fetal status.
• Severe abruptions are indicated by fetal distress or maternal hemodynamic instability. Initial
efforts should be focused on stabilization of the mother and delivery of the fetus. Hemorrhagic
shock requires vigorous blood and volume replacement with packed red blood cells (RBCs)
and crystalloids. Goals of blood and volume replacement are to maintain the hematocrit at
or above 30% and the urinary output at more than 0.5 mg/kg/hour. Platelet count, fibrinogen
level, and serum potassium level should be checked with every 4 to 6 units of packed RBCs
administered. If DIC is suspected, the institution’s massive transfusion protocol should be
activated. If fetal demise has occurred and maternal status is stable, vaginal delivery should
be attempted.
• Nonsevere abruptions: Maternal and fetal status should be continuously monitored. This includes
continuous fetal heart rate monitoring and tocometry, continuous monitoring of maternal vital
signs, securing at least one (preferably two) large-bore intravenous lines, and placement of an
indwelling catheter to allow for close monitoring of urinary output. Appropriate laboratory tests (see
later) should be performed and the blood bank notified. Finally, all providers should be prepared for
potential decompensation and the need for emergency caesarean delivery. Vaginal delivery may be
attempted as long as maternal and fetal statuses remain reassuring.
Other considerations:
• The patient should be tested for DIC every 4 hours until delivery. Fibrin degradation products
(D-dimers) are the most sensitive laboratory test, but once levels are elevated, they are not helpful
in guiding therapy.
• The ultimate therapy of DIC is delivery.
Partial separation
(concealed hemorrhage)
ABC
Partial separation
(apparent hemorrhage)
Complete separation
(concealed hemorrhage)
Figure 66-1. Drawings demonstrating different degrees of placental separation. A, Partial retroplacental abruption
(concealed hemorrhage): blood collects behind the placenta. B, Partial abruption: bleeding is observed dissecting along
the chorion and manifest (in this case) with vaginal bleeding. C, Complete abruption: blood collection anterior to the
placenta as the placenta completely separates from the uterine wall. (From Drife J, Magowan B. Clinical Obstetrics and
Gynaecology. Edinburgh: Saunders; 2004.)
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PLACENTA PREVIA AND PLACENTAL ABRUPTION 307
• If a cesarean delivery needs to be performed and the platelet count is lower than 50,000 or the
fibrinogen level is less than 100 mg/mL, these components should be replaced individually.
• Fibrinogen may be replaced with fresh frozen plasma or cryoprecipitate, although it is present in
greatest concentration in cryoprecipitate.
31. Which laboratory studies should be ordered in cases of suspected abruption?
Complete blood count, blood type, Rh status, and Kleihauer-Betke stain (to identify and quantify
fetal and maternal hemorrhage) should be ordered, as well as coagulation studies (prothrombin and
activated partial prothrombin time, fibrinogen, and D-dimers).
32. What is Couvelaire uterus?
Couvelaire uterus describes a finding at the time of laparotomy in which blood dissects into the
myometrium and gives the uterus a mottled, bluish color. It is a significant risk factor for uterine atony.
33. When should a pregnancy complicated by abruption be delivered?
The method and timing of delivery depend on the gestational age of the fetus and the severity of the
abruption. In cases of severe abruption, expeditious delivery is recommended at any gestational age.
If the fetus is immature and the status is reassuring, mild abruptions can be managed expectantly in
consultation with experts in high-risk pregnancies. Administration of corticosteroids to promote fetal
lung maturation is recommended between 24 and 34 weeks of gestation because these patients are
at risk of developing a sudden severe abruption. The development of coagulopathy, nonreassuring
fetal status, or intrauterine growth restriction is a possible indication for delivery.
34. What is the risk of recurrence of abruption in subsequent pregnancies?
The risk of recurrence has been reported to be 5% to 15%. After two consecutive abruptions, the risk
of a third rises to 20% to 25%. In cases of placental abruption resulting in fetal death, the recurrence
rate of repeat abruption resulting in the same outcome is approximately 11%.
BiBliography
1. Abenhaim HA, Azoulay L, Kramer MS, Leduc L. Incidence and risk factors of amniotic fluid embolisms: a
population-based study on 3 million births in the United States. Am J Obstet Gynecol. 2008;199:49.e1–49.e8.
2. American College of Obstetricians and Gynecologists. Medically indicated late-preterm and early-term deliveries.
ACOG committee opinion no. 560. Obstet Gynecol. 2013;121:908–910.
3. Ananth CV, Smulian JC, Demissie K, Vintzileos AM, Knuppel RA. Placental abruption among singleton and twin births
in the United States: risk factor profiles. Am J Epidemiol. 2001;153:771–778.
4. Breathnach FM, Donnelly J, Cooley SM, et al. Subclinical hypothyroidism as a risk factor for placental abruption:
evidence from a low-risk primigravid population. Aust N Z J Obstet Gynaecol. 2013;53:553–560.
5. Crane JM, van den Hof MC, Dodds L, Armson BA, Liston R. Neonatal outcomes with placenta previa. Obstet Gynecol.
1999;93:541–544.
6. Crane JM, Van den Hof MC, Dodds L, Armson BA, Liston R. Maternal complications with placenta previa. Am J Perinatol.
2000;17:101–105.
7. Cunningham F, Leveno KJ, Bloom SL, et al. Obstetrical hemorrhage. In: Williams Obstetrics. 24th ed. New York:
McGraw-Hill; 2013.
8. Dashe JS. Toward consistent terminology of placental location. Semin Perinatol. 2013;37:375–379.
9. Faiz AS, Ananth CV. Etiology and risk factors for placenta previa: an overview and meta-analysis of observational
studies. J Matern Fetal Neonatal Med. 2003;13:175–190.
10. Gabbe SG, Niebyl JR, Galan HL. Obstetrics: Normal and Problem Pregnancies. 6th ed. Philadelphia: Saunders; 2012.
11. Gemer O, Segal S. Incidence and contribution of predisposing factors to transverse lie presentation. Int J Gynaecol
Obstet. 1994;44:219–221.
12. Mendola P, Laughon SK, Männistö TI, et al. Obstetric complications among US women with asthma. Am J Obstet
Gynecol. 2013;208:127.e1–127.e8.
KEY POINTS: PLACENTAL ABRUPTION
1. Placental abruption is detachment of the placenta from its implantation site prior to delivery of the fetus.
2. Classic symptoms of placental abruption include vaginal bleeding, abdominal pain, and non-
reassuring fetal status or fetal demise.
3. Bleeding from an abruption is mostly maternal.
4. The method and timing of delivery depend on the gestational age of the fetus and the severity of the
abruption.
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308 LABOR, DELIVERY, AND POSTPARTUM
13. Olive EC, Roberts CL, Algert CS, Morris JM. Placenta praevia: maternal morbidity and place of birth. Aust N Z J Obstet
Gynaecol. 2005;45:499–504.
14. Oyelese Y, Ananth CV. Placental abruption. Obstet Gynecol. 2006;108:1005.
15. Pariente G, Wiznitzer A, Sergienko R, Mazor M, Holcberg G, Sheiner E. Placental abruption: critical analysis of risk
factors and perinatal outcomes. J Matern Fetal Neonatal Med. 2011;24:698–702.
16. Rosenberg T, Pariente G, Sergienko R, Wiznitzer A, Sheiner E. Critical analysis of risk factors and outcome of placenta
previa. Arch Gynecol Obstet. 2011;284:47–51.
17. Salihu HM, Li Q, Rouse DJ, Alexander GR. Placenta previa: neonatal death after live births in the United States.
Am J Obstet Gynecol. 2003;188:1305–1309.
18. Sheiner E, Shoham-Vardi I, Hallak M, Hershkowitz R, Katz M, Mazor M. Placenta previa: obstetric risk factors and
pregnancy outcome. J Matern Fetal Med. 2001;10:414–419.
19. Tikkanen M. Placental abruption: epidemiology, risk factors and consequences. Acta Obstet Gynecol Scand.
2011;90:140–149.
20. Warshak CR, Eskander R, Hull AD, et al. Accuracy of ultrasonography and magnetic resonance imaging in the
diagnosis of placenta accreta. Obstet Gynecol. 2006;108:573–581.
21. Yamada T, Yamada T, Morikawa M, Minakami H. Clinical features of abruptio placentae as a prominent cause of
cerebral palsy. Early Hum Dev. 2012;88:861–864.
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309
1. What is the definition of “fetal lie”?
Fetal lie refers to the orientation of the fetal spine in relation to the maternal spine. A fetus may be in a
longitudinal lie (fetal and maternal spines are oriented in the same direction), oblique lie, or transverse
lie. Normal fetal lie is longitudinal, which can be further divided into breech or cephalic depending on
the presenting part.
2. What are the possible types of cephalic presentations?
Most cephalic presentations are vertex (back of the fetal head as the presenting part). Occasionally,
face presentations occur. A brow presentation is an intermediate head position between vertex and
face presentation. It is rare and usually converts to another presentation.
3. Describe the various breech presentations.
• Frank breech: most common breech presentation, occurring when the fetal hips are flexed and the
knees extended
• Incomplete breech: incomplete flexion of one or both knees or hips
• Complete breech: when both the fetal knees and hips are flexed
Figure 67-1 contains illustrations of the breech positions.
4. How is fetal lie determined?
Ultrasound examination and Leopold maneuvers are commonly used. Leopold maneuvers are often
difficult to perform in obese patients.
CHAPTER 67
MALPRESENTATION
Jared Roeckner, MD
ABC
Figure 67-1. Breech presentations. A, Frank. B, Complete. C, Footling. (From Baskett TF. Breech delivery. In: Baskett TF,
ed. Munro Kerr’s Operative Obstetrics. 12th ed. London: Elsevier; 2014.)
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310 LABOR, DELIVERY, AND POSTPARTUM
5. What is an unstable lie?
This term is used to describe a situation characterized by frequent changes of either fetal lie or
presentation, or both.
6. What is the definition of fetal malpresentation?
Fetal malpresentation describes any presentation other than vertex.
7. How common is fetal malpresentation?
In preterm fetuses, malpresentation occurs quite often; approximately 25% of fetuses are breech
before 28 weeks of gestation. At term, the rate of malpresentation is 3% to 4%.
8. What delivery complication is more common with abnormal axial (also known as
transverse) lie?
Compared with a longitudinal lie with vertex presentation, prolapse of the umbilical cord occurs
approximately 20 times more often with an axial lie.
9. What factors have been linked to malpresentation?
• Maternal: pelvic tumors, uterine malformations, high parity
• Fetal: prematurity, multiple gestations, polyhydramnios, placenta previa or a fundal placenta,
chromosomal abnormalities (e.g., trisomies), myotonic dystrophy. Among fetuses with malpresentation,
fetal malformations are found more frequently.
10. What are the options for managing a patient at term with a singleton breech
pregnancy?
Options are expectant management (wait for the fetus change of a cephalic presentation), cesarean
delivery, external cephalic version (ECV), or breech vaginal delivery. Out of concern for increased
neonatal morbidity and mortality from breech vaginal delivery, cesarean delivery is the standard of
care. In cases of advanced labor, breech vaginal delivery may be considered. Breech delivery is also
an option for delivery of a second twin in appropriately selected patients.
11. What is external cephalic version (ECV)?
ECV is a procedure in which one or two people manually apply pressure to the maternal abdomen
to manipulate the fetus into a vertex presentation. Tocolytic agents and regional anesthesia are
sometimes employed to relax the uterus and increase the patient’s comfort. ECV is usually offered
as an option to patients at 36 to 37 weeks of gestation; attempts at later gestational age have lower
success, and earlier attempts carry a risk that the fetus will revert back to the previous position.
Rarely, ECV can cause fetal distress necessitating emergency delivery.
12. How successful are attempts at ECV?
The rate of success varies widely (35% to 85%) and averages approximately 58%. Low success rates
have been reported in nulliparous, obese women.
13. What are the absolute and relative contraindications to ECV?
Absolute contraindications are the same as those for vaginal delivery (e.g., placenta previa, human
immunodeficiency virus [HIV] infection with high viral load). Relative contraindications are not well
established and include active labor, fetal distress, multiple gestation, and amniotic fluid abnormalities
(polyhydramnios or oligohydramnios). A history of previous cesarean delivery or myomectomy is not a
contraindication.
14. What are the general steps to vaginal breech delivery?
1. Allowing the fetus to emerge spontaneously to the level of the umbilicus
2. Flexion of the fetal knee and delivery of the legs (Pinard maneuver)
3. Gentle rotation of the fetus to make the sacrum anterior
4. Gentle rotation of the trunk to allow the arms to be delivered by sweeping the elbows down across
the fetal chest
5. Supporting the trunk to allow for delivery of the shoulders and head
6. Application of suprapubic pressure by an assistant to promote flexion of the fetal head while
the delivering provider reaches into the vagina and gently applies pressure to the fetal maxilla
to maintain fetal head flexion during maternal expulsive efforts (Mauriceau Smellie Veit
maneuver)
Aside from emergency situations involving imminent delivery, breech vaginal delivery should be
attempted only by an experienced, trained provider after extensive counseling of the patient.
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MALPRESENTATION 311
15. What are potential complications of vaginal breech delivery?
Fetal limb injury, head entrapment, spinal cord injury, asphyxia, and death.
16. What is meant by “compound presentation”?
Compound presentation is when a fetal extremity (e.g., hand or arm) is located beside or in front of
the main presenting part. It occurs most frequently in premature infants and most often consists of a
combination of vertex position and an upper extremity. Vaginal delivery may still be possible, but an
experienced provider should be present. In general, compression or reduction of the compound part
should not be attempted.
BiBliography
1. American College of Obstetricians and Gynecologists. External cephalic version. ACOG practice bulletin no. 13. Int J
Gynaecol Obstet. 2000;2:198–204. Reaffirmed 2014.
2. American College of Obstetricians and Gynecologists. Mode of term singleton breech delivery. ACOG committee opinion
no. 265. Int J Gynaecol Obstet. 2002;77:65–66. Reaffirmed 2014.
3. American College of Obstetricians and Gynecologists. Mode of term singleton breech delivery. ACOG committee opinion
no 340. Obstet Gynecol. 2006;108:235–237.
4. de Hundt M, Velzel J, de Groot CJ, Mol BW, Kok M. Mode of delivery after successful external cephalic version: a
systematic review and meta-analysis. Obstet Gynecol. 2014;123:1327–1334.
5. Fruscalzo A, Londero AP, Salvador S, et al. New and old predictive factors for breech presentation: our experience in
14,433 singleton pregnancies and a literature review. J Matern Fetal Neonatal Med. 2014;27:167–172.
6. Gabbe S, Niebyl J, Simpsom J, et al., eds. Obstetrics: Normal and Problem Pregnancies. 6th ed. Philadelphia: Saunders;
2012.
KEY POINTS: MALPRESENTATION
1. Malpresentation is common early in pregnancy, but at term only 3% to 4% of fetuses are nonvertex.
2. Malpresentation at term is associated with an increased risk for fetal, placental, and uterine anoma-
lies compared with vertex presentation.
3. Cesarean delivery of a breech fetus is the standard of care out of concern for increased neonatal
morbidity and mortality from breech vaginal delivery.
4. External version is a technique in which one attempts to maneuver a fetus from breech to cephalic
presentation.
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312
1. What is postpartum hemorrhage?
Postpartum hemorrhage is defined as an estimated blood loss greater than 500 mL after a vaginal
delivery and greater than 1000 mL after a cesarean delivery. It is one of the leading causes of maternal
morbidity and mortality; approximately 140,000 women worldwide die of postpartum hemorrhage each
year. Early or primary postpartum hemorrhage occurs within the first 24 hours of delivery, whereas
late or secondary hemorrhage can occur anywhere from 24 hours after delivery to up to 6 to 12 weeks
post partum.
2. What causes postpartum hemorrhage?
• Uterine atony
• Retained placental tissue
• Genital tract trauma
• Coagulation defects
• Uterine inversion
The most common cause of postpartum hemorrhage is uterine atony (80%), which is defined as the
inability of the uterus to contract fully after delivery. Several risk factors for uterine atony have been
identified (Box 68-1).
3. What should be considered in the initial evaluation of a patient with early
postpartum hemorrhage?
A bimanual examination should be performed to determine whether uterine atony is present. Uterine
massage or bimanual uterine compression can decrease bleeding and help expel clots. A full bladder
can inhibit complete contraction of the lower uterine segment, so a urinary catheter should be placed.
The patient should be carefully examined for any unrecognized vaginal or cervical lacerations. It is
prudent to ensure that the patient have adequate intravenous access and fluid resuscitation, and
blood replacement products should be readily available.
4. What are the different uterotonics available to treat uterine atony?
Uterotonics are first-line treatments for hemorrhage secondary to atony. These agents are summarized
in Table 68-1.
5. What other options are available if uterotonics fail to stop the bleeding?
Tamponade techniques, embolization, and surgical intervention. Tamponade techniques include
uterine packing, insertion of one or more Foley catheter bulbs into the uterus and instilling each with
60 to 80 mL of saline, or placement of the Bakri balloon (inserted into the uterus and filled with 300
to 500 mL of saline). If patients are stable, arterial embolization by interventional radiology may be
considered. Surgical procedures for obstetric hemorrhage are listed in Box 68-2.
6. What if the hemorrhage is not caused by atony?
Heavy bleeding in a patient with a contracted, firm uterus should raise concern for retained placental
fragments, unrecognized lacerations, or uterine rupture. Placenta accreta (trophoblastic invasion past
CHAPTER 68
POSTPARTUM HEMORRHAGE
Shant Ashdjian, MD
• History of postpartum hemorrhage
• High parity
• Protracted labor
• Precipitous labor
• Overdistention of the uterus (e.g., macrosomia, multiple gestation, polyhydramnios)
Box 68-1. Risk Factors for Uterine Atony
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