trial

be adjusted to improve the fit over the fetal skull by adjusting Vaginal Bleeding
the position of the calipers. Clinical Pearls:

The AC is measured in a symmetrical, circular, transverse •" The differential diagnosis of second and third trimester
section of the fetal abdomen. Anatomic landmarks to identify vaginal bleeding includes multiple obstetric complications that
the proper plane of measurement include: visualization of the are associated with increased maternal and fetal morbidity
vertebrae in cross section along with the stomach bubble, and and mortality.
intrahepatic umbilical vein with portal sinus. The fetal kidneys
should not be visualized. Measuring the AC with the fetal •" Bleeding in the second and third trimester requires timely
spine at 3 o’clock or 9 o’clock will minimize shadowing. maternal/fetal clinical assessment and ultrasonography, which
Similar to measurement of the HC, after selecting AC from the will guide diagnosis and management
biometry menu, calipers will appear. Place the proximal and
distal calipers on the outer edges of the fetal skin such that Vaginal bleeding in the second or third trimester complicates
the line between them is perpendicular to the midline. Open approximately 6% of all pregnancies.(14, 15) The differential
and fit the ellipse over the contour of the fetal abdomen. The diagnosis of bleeding in the latter half of pregnancy includes
ellipse can be adjusted to improve the fit by adjusting the labor/preterm labor, cervical insufficiency, placenta previa,
caliper position. placental abruption, uterine rupture, vasa previa as well as
cervical or vaginal pathology such as polyps, inflammation/
FL should be measured with the full length of the bone infection, trauma, or cervical carcinoma among other
perpendicular to the ultrasound beam, excluding the etiologies. Time permitting, the six-step systematic scanning
epiphysis. The measurement is obtained by selecting FL from approach should be followed with particular emphasis on
the biometry menu and placing the calipers at the ends of the placental assessment and placental location. It is important
ossified diaphysis. to note that all steps do not need to be performed if the
patient has already previously been scanned and the exam
Typically, ultrasound machines have software that derives the can be tailored to the clinical circumstance. While
estimated fetal weight from the biometric measurements transvaginal (TV) imaging is the preferred methodology for
using a mathematical formula. A complete discussion of the placental imaging, the following sections will focus on
methodology of estimation of fetal weight is beyond the scope abdominal ultrasound, which is typically more readily
of this iBook. available in the setting of an acutely bleeding patient.

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Placenta previa placenta previa extends to the edge of the internal cervical os
but does not cover it.
Placenta previa occurs when the placenta covers the internal
os of the cervix and affects approximately 1 in 200 Placenta accreta
pregnancies at term.(16) A recent consensus workshop
changed the nomenclature for placenta previa, which is Placenta accreta describes abnormal placental implantation
defined as any placenta that overlies the cervical os to any where trophoblastic invasion and placental villi extend beyond
degree.(11) All placentas that approach, but are not the normal decidual boundary (Nitabuch’s layer) and is
overlying, the cervical os are termed “low lying”.(11) Risk defined according to the depth of placental invasion. The
factors for placenta previa include a history of cesarean term placenta accreta refers to the attachment of chorionic
delivery, dilation and curettage, previous placenta previa, villi to the myometrium. Placenta increta and percreta refer to
advanced maternal age, and tobacco abuse.(17) Importantly, invasion into the myometrium and to or beyond the uterine
while many placentas extend into the lower uterine segment serosa respectively. Placenta accreta is associated with
in early pregnancy, the majority “migrate” away from the multiple risk factors, the strongest of which are placenta
cervix with advancing gestation as the lower uterine segment previa and previous uterine surgery (especially cesarean
develops and as placental growth progresses toward the delivery). Importantly, placenta accreta is associated with a
better vascularized (fundal) portion of the uterus marked increase in maternal morbidity and mortality.(20) The
(trophotropism). Persistence of placenta previa until delivery majority of maternal complications result from massive
is associated with a later gestational age at diagnosis and a hemorrhage (DIC, massive transfusion, multiorgan failure,
greater distance of extension of the placenta over the internal additional surgical procedures or interventions,
cervical os.(18, 19) Classically, placenta previa presents with thromboembolism, infection, ARDS) while fetal morbidity is
painless vaginal bleeding, however some women may increased secondary to prematurity. Comprehensive reviews
present with uterine contractions and bleeding which may on the diagnosis, management and morbidity of placenta
overlap with the clinical presentation of placenta abruption. accreta have been published recently.(17, 20) Ultrasound is
The diagnosis of placenta previa requires delivery by the cornerstone of antenatal diagnosis of placenta accreta.
cesarean section. The sonographic findings of placenta Ultrasound findings suggesting placenta accreta include
previa will be based on the relationship of the placental edge multiple vascular lacunae within the placenta (“Swiss cheese
to the internal cervical os. A complete placenta previa will appearance”) with or without turbulent flow, loss of the normal
cover the internal cervical os completely while a marginal hypoechoic retroplacental area, abnormal appearance of the

101

interface of the uterine serosa and bladder, and retroplacental abdominal pain. Back pain may occur if the placenta is

myometrial thickness < 1 mm.(21) posterior. The majority of cases of clinical placental abruption

Placental abruption (abruptio placenta will not be detected by ultrasound so the absence of
sonographic findings of placental abruption does not rule out

Placental abruption (Gallery GALLERY 8.1 Abruptio Placenta the diagnosis.(24)
8.1), or premature placental Sonographic findings include
separation with bleeding at the Hypoechoic retroplacental hematoma (measured area) in a the presence of a hematoma
placental-decidual interface, patient with abruptio placenta. Image courtesy of Jane that is the result of the
affects approximately 1% of all Cortville, MD. separation. The hematoma will
pregnancies and is associated usually be located
with an increased risk of retroplacental but it can also be
maternal and fetal morbidity and located preplacental
mortality.(22, 23) Numerous (subamniotic). The sonographic
risk factors for placental appearance of the hematoma
abruption have been identified can vary and may be
and risk factors include: chronic hypoechoic, isoechoic, or
hypertension, gestational hyperechoic to the surrounding
hypertension, preeclampsia or tissue. Visualization of a
eclampsia, premature rupture of retroplacental clot has a high
membranes, trauma, cocaine positive predictive value for
use, prior placental abruption, abruption, however this typically
polyhydramnios, and correlates with a substantial
intrauterine growth restriction. quantity of bleeding and/or
Importantly, the diagnosis of placental separation.

placental abruption is based on Vasa previa
clinical findings, including

vaginal bleeding accompanied by abdominal or uterine pain. Vasa previa (Gallery 8.2), a rare but potentially catastrophic

Examination may reveal uterine tenderness, frequent uterine complication, occurs when fetal vessels are present in the

contractions (≥ every 2 minutes or uterine tetany) or constant

102

membranes covering the cervical os. A vasa previa can form be confirmed on TV ultrasound with color Doppler

in the following two scenarios: documenting the presence of fetal vessels overlying the

•" Velamentous insertion of umbilical cord, with umbilical internal os. Pulsed Doppler should be performed to ensure
the vascular flow is fetal in origin (and not maternal/uterine).
vessels coursing through the fetal membranes before
Consideration should be given
inserting into placental disk GALLERY 8.2 Vasa Previa to performing or repeating the
•" Bilobed or succenturiate study in the Trendelenburg
position or after the patient
placenta, with connecting fetal moves around to ensure a funic
(umbilical cord) presentation is
vessels in the membranes ruled out.

overlying the cervix

Undiagnosed vasa previa

carries a perinatal mortality rate

of approximately 60% as a Abdominal Pain
result of fetal/neonatal

exsanguination upon Clinical Pearls:

spontaneous or artificial rupture Note the presence of fetal blood vessels crossing the inter- •" The physiologic and
of membranes.(25) Prior to the nal orifice of the cervix (vasa previa). Image courtesy of anatomic changes of pregnancy
incorporation of ultrasound into Lara Bohinc, RDMS. may alter the clinical
prenatal care, the morbidity presentation and examination of
from vasa previa was thought to the pregnant woman with acute
be unavoidable. However, in abdominal pain
the era of ultrasound the
majority of morbidity from vasa •" Point-of-care ultrasound

previa is circumvented with provides a rapid, safe and

prenatal diagnosis and effective way to distinguish

cesarean delivery prior to the onset of labor. between some of the obstetric and non-obstetric etiologies of

Flow within the vessels overlying the internal cervical os will acute abdominal pain

be seen with TA ultrasound. The diagnosis of vasa previa can

103

The approach to acute abdominal pain in pregnancy, while more thorough evaluation of the right upper quadrant with
similar to the non-pregnant state, also includes the challenges transverse view of the liver may reveal a subcapsular
of the physiologic and anatomic changes of pregnancy, hematoma, as evidenced by a curvilinear, anechoic collection
obstetric etiologies of pain, as well as maternal and fetal between the liver and the capsule.
implications of the underlying pathologic process. The
primary goal in the evaluation of patients with acute (2) Rectus sheath hematoma: Rectus sheath hematomas,
abdominal pain is to identify those with serious etiologies that either traumatic or spontaneous, represent a rare cause of
require urgent intervention. Rather than present a acute abdominal pain; however, pregnancy is a known risk
comprehensive review of the differential diagnosis and factor.(26) Ultrasound is an appropriate screening test prior
management of the acute abdomen, this section will focus on to CT or surgical intervention.(27) Transverse imaging of the
elements of the differential diagnosis that may be identified or abdominal wall (perpendicular to the rectus bellies) will
ruled out with point-of-care ultrasound. These patients should demonstrate a heterogeneous appearance and intra-
undergo the six-step systematic approach along with abdominal free fluid will be absent. It is important to note that
additional abdominal scanning to assess non-obstetrical ultrasound cannot be used to distinguish a hematoma from an
causes of abdominal pain based on the individual clinical abscess.
circumstance. It is beyond the scope of this iBook to discuss
the sonographic evaluation and findings of the non-obstetrical (3) Hernia: While ventral and groin hernias are typically
abdominal ultrasound examination. readily identified with abdominal and groin examination,
ultrasound may be used as an adjunct to physical
This section will highlight examples of point-of-care examination. Ultrasound over the suspected hernia site may
ultrasound findings and techniques to aid diagnosis in the detect fascial defects, protrusion or herniation of fat or small
setting of the acute abdomen in pregnancy. Examples bowel, and may detect other pathologies such as fluid
covered elsewhere in this iBook will not be discussed. collections.(28)

(1) Pregnancy-related liver disease: Subcapsular hepatic (4) Ovarian torsion: While primarily a clinical diagnosis,
hematoma (with or without rupture) is a rare complication of numerous ultrasound findings may suggest ovarian torsion in
HELLP syndrome that is a surgical emergency. Performance a symptomatic patient with an adnexal mass of appropriate
of a FAST ultrasound may detect intra-abdominal free fluid. A size (approximately 5cm or greater).(29, 30) While torsion
can occur at any point in pregnancy, diagnosis prior to 20
weeks is more common given that the gravid uterus may

104

prevent ovarian torsion due to intra-abdominal space central degeneration. Additionally, the performance of
constraints. (30) Ultrasound findings suggestive of torsion ultrasonography overlying the degenerating fibroid typically
include.(31) reproduces patient abdominal pain. Lastly, a degenerating
pedunculated fibroid (particularly with lateral location) may
•" Enlarged ovary with cyst or mass mimic a cystic ovarian mass."

•" Heterogeneous appearance to ovarian stroma (due to Management of Obstetric Trauma
edema and/or hemorrhage) Clinical Pearls:

•" Decreased or absent ovarian Doppler flow •" The priority in treating a pregnant trauma victim is
stabilization of the mother.
•" Abnormal ovarian location (example: anterior to uterus)

•" Free pelvic fluid

Given that the ovary has dual arterial supply (from both the
ovarian artery and collateral supply from the uterus through
the utero-ovarian ligament), diminished or absent flow,
particularly as an isolated finding, does not accurately predict
ovarian torsion.(32)

(5) Fibroid degeneration: While the majority of fibroids remain
asymptomatic in pregnancy, fibroid degeneration can occur in
pregnancy when rapid fibroid growth results in a relative
decrease in perfusion leading to ischemia and necrosis.
Larger fibroids are at a greater risk to undergo degeneration
in pregnancy.(33) In addition to localized pain, the release of
prostaglandins from degenerating fibroids may also result in
the clinical findings of fever, nausea or mild leukocytosis. By
ultrasound, degenerating fibroids may demonstrate cystic,

105

•" Ultrasound evaluation as part of the secondary survey in receive care in a designated trauma center, which suggests
pregnant trauma patients should focus on the determination that a coordinated approach to trauma care may improve
of gestational age and the presence of fetal cardiac activity maternal and neonatal outcomes.(38) As such, we
(viability), placental location, fetal number, and fetal encourage a standardized approach to the triage and
presentation. evaluation of pregnant trauma patients based on the local
availability of resources. The six-step systematic approach
•" While periviable birth occurs between 20-25 weeks’ GA, should be tailored to the individual clinical circumstance and
in the United States, interventions for fetal benefit are not the eFAST examination should be performed if there is
typically performed before 23-24 weeks’ GA.. concern for blunt thoracic and/or abdominal trauma (Gallery

•" Position the second/third trimester trauma patient in the GALLERY 8.3 eFAST Examination Windows
left lateral decubitus position to avoid compressing the inferior
vena cava. eFAST examination sonographic windows: pericardial, peri-
hepatic, pelvic, perisplenic, and thoracic.
Trauma complicates as many as 1 in 12 pregnancies and is
the leading cause of non-obstetric maternal mortality in the 106
United States.(34, 35) Maternal trauma is associated with
multiple adverse obstetric outcomes including premature
rupture of membranes, preterm labor and preterm birth,
placental abruption, cesarean delivery, uterine rupture and
intrauterine fetal demise.(36) While pregnancy does not
appear to impact morbidity and mortality related to trauma,
the physiologic changes of pregnancy may alter clinical
presentation, for example by masking early signs of severe
hemorrhage. Additionally, the gravid uterus may alter patterns
of injury, particularly for penetrating trauma.(37)

In this chapter we will review the use of ultrasound
applications in the setting of trauma in pregnancy. Recent
evidence demonstrates a decrease in the rate of preterm
delivery for pregnant women with traumatic injuries who

8.1). An overview of the eFAST examination is beyond the United States, management decisions based on fetal
scope of this iBook so it is recommended that the ACEP indications (fetal monitoring, cesarean delivery) are
Trauma App be downloaded (no cost) from Apple’s App Store incorporated into care beginning at 23-24 weeks of gestation.
for a comprehensive discussion of the eFAST examination.
Determining gestational age of the fetus should be done by
Management of the Pregnant Trauma Patient physical examination with assessment of fundal height. If this
cannot be done, then a quick assessment of fundal height in
The primary management goal in caring for the pregnant relationship to the umbilicus should be performed. Provided
trauma patient is maternal stabilization. Fetal outcomes that the patient does not have uterine fibroids, the fundal
directly correlate with early and aggressive maternal height measurement will provide a good estimate of
resuscitation, and as such pregnancy should not result in gestational age and help the clinician in determining if the
under-diagnosis or treatment secondary to fears of any fetus is independently viable. Femur length may also be used
adverse fetal effects.(36, 39) Simultaneous evaluation of to estimate GA. If fetal viability is confirmed, the initiation of
pregnant trauma patients by emergency, trauma and continuous external fetal monitoring is recommended along
obstetrical teams should be undertaken when possible to with external tocometry to assess for clinical evidence of
provide the most rapid, comprehensive assessment. A preterm labor or placental abruption.
comprehensive review detailing the care of pregnant trauma
patients can be found in recent publications and proposed (1) Ultrasound for Secondary Obstetric Survey:
management algorithms.(36, 39, 40)
Ultrasound evaluation as part of the secondary survey in
Viability determination pregnant trauma patients should focus on the determination
of gestational age and the presence of fetal cardiac activity
The gestational age at which “viability” is determined is (viability), placental location, fetal number, and fetal
dependent on local resources for neonatal resuscitation, with presentation. Knowledge of placental location and fetal
large discrepancies between resource-rich and resource-poor presentation provide useful information for delivery planning
settings.(41, 42). As such, decisions regarding interventions should delivery become indicated. The technique for
for fetal benefit may vary widely by country or practice setting. performing these evaluations does not differ from those
In the United States, as outlined by a recent multi-society described earlier in this book. However, the point-of-care
consensus workshop, periviable birth is defined as delivery at sonologist must remain attentive to the mechanism of injury
20 0/7 to 25 6/7 weeks of gestation.(43) In general in the and the time required to perform the obstetric assessment as

107

this ultrasound exam should be performed in a purposeful, on the anatomic location of other abdominal viscera.
timely manner. For example, determination of gestational age Additionally, a FAST exam in a supine pregnant woman
in the setting of critical maternal illness can be determined should be performed with left lateral displacement if possible.
rapidly by assessment of fundal height or FL alone.
Management of the Critically Ill Obstetric Patient
Importantly, the use of ultrasound for the diagnosis of Clinical Pearls:
placental abruption remains limited. The sensitivity of
ultrasound for the detection of placental abruption is low (24% •" Goals of point-of-care ultrasound in second and third
in one study), however when a clot is visualized the positive trimester critically ill patients include determining fetal number,
predictive value for the detection of abruption at delivery is viability, and gestational dating.
high.(24) In this 2002 study, 50% of women with a clinical
abruption, confirmed at delivery, had negative sonographic Point-of-care ultrasound in critically ill obstetric patients
findings.(24) Clinically, a substantial quantity of blood must
collect to be evident by ultrasound. Additionally, since most The second or third trimester patient with a critical illness
abruptions are not concealed, vaginal bleeding may preclude (medical or surgical/traumatic) requires rapid evaluation and
the development of a sonographically evident abruption. resuscitation. The primary goal of the point-of-care second or
third trimester ultrasound examination in a patient with an
(2) Focused Assessment with Sonography for Trauma (FAST) unknown prenatal/OB history should be determination of fetal
number, viability, and gestational age. Ideally in these
The American Institute of Ultrasound in Medicine published a critically ill patients, assessment of the placenta and its
detailed description of FAST practice guidelines in 2014.(45) location would not be of clinical significance since the method
FAST may be used in both the non-pregnant and pregnant of delivery in these unstable obstetrical patients would be by
patient populations to diagnose traumatic injuries. A large cesarean section. In patients with routine prenatal care and
retrospective cohort study has demonstrated that the ultrasound examinations, fetal viability may be the only
sensitivity and specificity of FAST for the detection of free element that needs to be determined if the patient’s records
intraperitoneal fluid or intraabdominal injury is similar between can be quickly assessed by another member of the
pregnant and non-pregnant trauma patients.(46) healthcare team while resuscitative efforts are continued.

The technique for performance of a FAST exam in a pregnant Perimortem Cesarean Delivery
trauma does not differ compared with a non-pregnant patient.
However, remember to consider the impact of a gravid uterus 108

In the setting of maternal cardiac arrest (or severe maternal six steps. In patients in active labor, the examination should
injury or illness requiring cardiopulmonary resuscitation), a focus on fetal presentation and placental localization along
perimortem cesarean section on a viable pregnancy may with fetal viability in order to determine the need for cesarean
improve maternal and neonatal mortality. While the data is delivery. In patients with imminent delivery, it would be very
limited to retrospective case reports and series, cesarean unlikely that POCUS would be helpful and it would most likely
delivery performed within 4 minutes of unsuccessful maternal interfere with delivery efforts and medical management.
cardiopulmonary resuscitation (CPR) may improve maternal
and infant survival.(47) Theoretically, and supported by Postpartum Hemorrhage (PPH)
anecdotal evidence, delivery in the setting of unsuccessful Clinical Pearls:
maternal CPR may improve hemodynamics and resuscitative
efforts.(48, 49) Prior to viability, a cesarean section would be •" POCUS can assist in the diagnosis and management of
unlikely to impact the mechanical and volume hemodynamics primary and secondary postpartum hemorrhage.
of the pregnant uterus on maternal resuscitation. In the
setting of maternal cardiac arrest, point-of-care ultrasound if •" Procedures for the treatment of postpartum hemorrhage
performed at all should be very brief and should not distract can be performed under direct ultrasound guidance.
from the resuscitative efforts.
In the postpartum period, POCUS may be helpful in the
Active Labor/Imminent Delivery diagnosis and management of postpartum hemorrhage
Clinical Pearls: (PPH). PPH, which affects approximately 6% of all deliveries,
remains one of the leading causes of maternal death
•" POCUS in the active labor patient should focus on fetal worldwide, with approximately 140,000 deaths annually.(50,
presentation, placenta location, and fetal viability. 51) Classically, PPH is defined based on the quantity of blood
loss, most commonly as ≥ 500 mL after a vaginal delivery and
The decision to perform POCUS in the evaluation of the ≥ 1000 mL after a cesarean delivery. PPH can also be
patient in active labor should be based on the patient’s history defined as primary (occurring in the first 24 hours after
and current examination. Patients who have had routine delivery) or secondary (occurring from 24 hours to 12 weeks
prenatal care with prenatal ultrasound examinations at most after delivery).(50) In this chapter, we will review ultrasound
would require a very brief tailored examination. The patient applications useful in the management of primary and
without prenatal care would, time permitting, require a secondary PPH. A full discussion of the epidemiology,
sonographic evaluation that would include most (or all) of the
109

identification, management, and prevention of PPH is beyond impregnated with thrombin (5000 units of thrombin in 5mL of
the scope of this text. sterile saline) to enhance clotting. "

Primary PPH Uterine balloons or packing can be placed under ultrasound
guidance. The transducer should be placed in sagittal position
Primary PPH may result from uterine atony, tissue trauma or superior to the pubic symphysis in the midline of the maternal
lacerations, retained products of conception, coagulopathy, or abdomen. By convention, the notch should be pointing to the
a combination of these factors. In the setting of primary PPH, maternal head, which will allow for the fundus to be on the left
point-of-care ultrasound can provide a useful tool to assist side of the screen. In this position, a uterine balloon can be
with diagnosis and treatment. For example, ultrasound may inserted and filled under direct visualization.
aid in the identification of retained placenta (in conjunction
with clinical exam/uterine exploration) or abnormal Retained Placenta
placentation (placenta accreta). Additionally, procedures for
retained placenta (such as uterine curettage) or uterine atony Ultrasound can be used to identify retained placental tissue.
refractory to initial medical management with uterotonic A thin endometrial echo should be present after delivery with
agents (uterine tamponade or packing) can be performed complete placental expulsion. Retained placental tissue can
under ultrasound guidance to minimize the risks of uterine be identified as an irregular, echoic mass adjacent to the
perforation and to assess the adequacy of treatment. uterine lining. In the setting of acute, or primary PPH,
retained placental tissue should demonstrate vascular flow by
Uterine Tamponade Doppler.

Uterine tamponade, either with a balloon catheter or packing, Assessment for retained placenta by ultrasound requires
is an effective treatment for PPH secondary to uterine atony. assessment of the uterus both the sagittal and transverse
We recommend the use of uterine balloons, if available, over planes. The sagittal plane can be assessed with the same
uterine packing given that they can be placed quickly and technique as described for uterine tamponade. For
easily, allow for objective quantification of ongoing blood loss, transverse assessment, rotate the transducer 90° (transverse
and are likely more effective than packing.(52, 53) on maternal abdomen) and scan from the fundus to the lower
Furthermore, early use of balloon tamponade is associated uterine segment in the midline of the maternal abdomen.
with a decreased risk of transfusion, ICU admission, and Uterine curettage can be performed under ultrasound
hysterectomy.(54) If a balloon is not available, gauze or kerlix guidance using a sagittal in-plane technique through the long
can be used to pack the uterine cavity and can be axis of the uterus.

110

Assessment of Ongoing Bleeding 1 Practice ACoO. ACOG Committee Opinion No. 340. Mode
of term singleton breech delivery. Obstet Gynecol. 2006 Jul;
POCUS can be used to evaluate ongoing bleeding in the 108(1):235-7.
setting of primary PPH. Blood, which is anechoic (dark) on
ultrasound can be seen filling and distending the uterus in 2 Abramowicz JS. Benefits and risks of ultrasound in
women with ongoing bleeding. pregnancy. Semin Perinatol. 2013 Oct;37(5):295-300.

Secondary PPH 3 American College of O, Gynecologists, Society for Maternal-
Fetal M. ACOG Practice Bulletin No. 144: Multifetal
Ultrasound examination is also central to the diagnostic gestations: twin, triplet, and higher-order multifetal
evaluation of secondary PPH. The postpartum uterus has a pregnancies. Obstet Gynecol. 2014 May;123(5):1118-32.
variable appearance on ultrasound with significant overlap
between the findings in normal and pathologic states.(55, 56) 4 Ross M, Beall M. Amniotic fluid dynamics. In: Creasy R,
As such, the interpretation of postpartum uterine ultrasound Resnik R, Iams J, editors. Maternal-Fetal Medicine Principles
images can be challenging. In both the normal postpartum and Practice. 7th ed. Philadelphia, PA: Saunders; 2013. p.
state and secondary PPH, the uterus may be empty or 47-52.
contain fluid or echogenic material. Echogenic intrauterine
material with vascularity on color Doppler suggests retained 5 Chamberlain PF, Manning FA, Morrison I, Harman CR,
placenta. While a lack of vascularity may indicate that Lange IR. Ultrasound evaluation of amniotic fluid volume. II.
intrauterine material is a blood clot, avascular or necrotic The relationship of increased amniotic fluid volume to
retained placenta cannot be excluded. While rare, gestational perinatal outcome. Am J Obstet Gynecol. 1984 Oct 1;150(3):
trophoblastic disease and uterine arteriovenous 250-4.
malformations are part of the differential diagnosis which can
be assessed by ultrasound. In conjunction with ultrasound, 6 Gumus, II, Koktener A, Turhan NO. Perinatal outcomes of
serum quantitative hCG may be useful for the detection of pregnancies with borderline amniotic fluid index. Arch
retained products of conception, choriocarcinoma, or a new Gynecol Obstet. 2007 Jul;276(1):17-9.
pregnancy. The technique for uterine imaging in the setting of
secondary PPH is similar to that described for primary PPH. 7 Volante E, Gramellini D, Moretti S, Kaihura C, Bevilacqua
G. Alteration of the amniotic fluid and neonatal outcome. Acta
References: Biomed. 2004;75 Suppl 1:71-5.

111

8 Locatelli A, Vergani P, Toso L, Verderio M, Pezzullo JC, 13 Committee opinion no 611: method for estimating due
Ghidini A. Perinatal outcome associated with oligohydramnios date. Obstet Gynecol. 2014 Oct;124(4):863-6.
in uncomplicated term pregnancies. Arch Gynecol Obstet.
2004 Jan;269(2):130-3. 14 Calleja-Agius J, Custo R, Brincat M, Calleja N. Placental
abruption and placena praevia. Eur Clin Obstet Gynaecol.
9 Pilliod RA, Page JM, Burwick RM, Kaimal AJ, Cheng YW, 2006;2:121-7.
Caughey AB. The risk of fetal death in nonanomalous
pregnancies affected by polyhydramnios. Am J Obstet 15 Antepartum Haemorrhage; Royal College of Obstetrician
Gynecol. 2015 Sep;213(3):410 e1-6. and Gynaecologists, Green Top Guideline Number 63.
December 2011.
10 Nabhan AF, Abdelmoula YA. Amniotic fluid index versus
single deepest vertical pocket as a screening test for 16 Faiz AS, Ananth CV. Etiology and risk factors for placenta
preventing adverse pregnancy outcome. Cochrane Database previa: an overview and meta-analysis of observational
Syst Rev. 2008(3):CD006593. studies. J Matern Fetal Neonatal Med. 2003 Mar;13(3):
175-90.
11 Reddy UM, Abuhamad AZ, Levine D, Saade GR, Fetal
Imaging Workshop Invited P. Fetal imaging: executive 17 Silver RM. Abnormal Placentation: Placenta Previa, Vasa
summary of a joint Eunice Kennedy Shriver National Institute Previa, and Placenta Accreta. Obstet Gynecol. 2015 Sep;
of Child Health and Human Development, Society for 126(3):654-68.
Maternal-Fetal Medicine, American Institute of Ultrasound in
Medicine, American College of Obstetricians and 18 Dashe JS, McIntire DD, Ramus RM, Santos-Ramos R,
Gynecologists, American College of Radiology, Society for Twickler DM. Persistence of placenta previa according to
Pediatric Radiology, and Society of Radiologists in Ultrasound gestational age at ultrasound detection. Obstet Gynecol. 2002
Fetal Imaging workshop. Obstet Gynecol. 2014 May;123(5): May;99(5 Pt 1):692-7.
1070-82.
19 Becker RH, Vonk R, Mende BC, Ragosch V, Entezami M.
12 American College of O, Gynecologists. ACOG committee The relevance of placental location at 20-23 gestational
opinion no. 560: Medically indicated late-preterm and early- weeks for prediction of placenta previa at delivery: evaluation
term deliveries. Obstet Gynecol. 2013 Apr;121(4):908-10. of 8650 cases. Ultrasound Obstet Gynecol. 2001 Jun;17(6):
496-501.

112

20 Publications Committee SfM-FM, Belfort MA. Placenta 28 Young J, Gilbert AI, Graham MF. The use of ultrasound in
accreta. Am J Obstet Gynecol. 2010 Nov;203(5):430-9. the diagnosis of abdominal wall hernias. Hernia. 2007 Aug;
11(4):347-51.
21 Gielchinsky Y, Mankuta D, Rojansky N, Laufer N,
Gielchinsky I, Ezra Y. Perinatal outcome of pregnancies 29 Varras M, Tsikini A, Polyzos D, Samara C, Hadjopoulos G,
complicated by placenta accreta. Obstet Gynecol. 2004 Sep; Akrivis C. Uterine adnexal torsion: pathologic and gray-scale
104(3):527-30. ultrasonographic findings. Clin Exp Obstet Gynecol.
2004;31(1):34-8.
22 Ananth CV, Berkowitz GS, Savitz DA, Lapinski RH.
Placental abruption and adverse perinatal outcomes. JAMA. 30 Koo YJ, Kim TJ, Lee JE, et al. Risk of torsion and
1999 Nov 3;282(17):1646-51. malignancy by adnexal mass size in pregnant women. Acta
Obstet Gynecol Scand. 2011 Apr;90(4):358-61.
23 Ananth CV, Wilcox AJ. Placental abruption and perinatal
mortality in the United States. Am J Epidemiol. 2001 Feb 31 Dupuis CS, Kim YH. Ultrasonography of adnexal causes of
15;153(4):332-7. acute pelvic pain in pre-menopausal non-pregnant women.
Ultrasonography. 2015 Oct;34(4):258-67.
24 Glantz C, Purnell L. Clinical utility of sonography in the
diagnosis and treatment of placental abruption. J Ultrasound 32 Mashiach R, Melamed N, Gilad N, Ben-Shitrit G, Meizner I.
Med. 2002 Aug;21(8):837-40. Sonographic diagnosis of ovarian torsion: accuracy and
predictive factors. J Ultrasound Med. 2011 Sep;30(9):
25 Oyelese KO, Turner M, Lees C, Campbell S. Vasa previa: 1205-10.
an avoidable obstetric tragedy. Obstet Gynecol Surv. 1999
Feb;54(2):138-45. 33 Strobelt N, Ghidini A, Cavallone M, Pensabene I, Ceruti P,
Vergani P. Natural history of uterine leiomyomas in pregnancy.
26 Kasotakis G. Retroperitoneal and rectus sheath J Ultrasound Med. 1994 May;13(5):399-401.
hematomas. Surg Clin North Am. 2014 Feb;94(1):71-6.
34 Hill CC, Pickinpaugh J. Trauma and surgical emergencies
27 Klingler PJ, Wetscher G, Glaser K, Tschmelitsch J, Schmid in the obstetric patient. Surg Clin North Am. 2008 Apr;88(2):
T, Hinder RA. The use of ultrasound to differentiate rectus 421-40, viii.
sheath hematoma from other acute abdominal disorders.
Surg Endosc. 1999 Nov;13(11):1129-34. 113

35 Fildes J, Reed L, Jones N, Martin M, Barrett J. Trauma: 43 American College of O, Gynecologists, Society for
the leading cause of maternal death. J Trauma. 1992 May; Maternal-Fetal M. ACOG Obstetric Care Consensus No. 3:
32(5):643-5. Periviable Birth. Obstet Gynecol. 2015 Nov;126(5):e82-94.

36 Mendez-Figueroa H, Dahlke JD, Vrees RA, Rouse DJ. 44 Schiff MA, Holt VL. Pregnancy outcomes following
Trauma in pregnancy: an updated systematic review. Am J hospitalization for motor vehicle crashes in Washington State
Obstet Gynecol. 2013 Jul;209(1):1-10. from 1989 to 2001. Am J Epidemiol. 2005 Mar 15;161(6):
503-10.
37 El Kady D. Perinatal outcomes of traumatic injuries during
pregnancy. Clin Obstet Gynecol. 2007 Sep;50(3):582-91. 45 American Institute of Ultrasound in M, American College of
Emergency P. AIUM practice guideline for the performance of
38 Distelhorst JT, Krishnamoorthy V, Schiff MA. Association the focused assessment with sonography for trauma (FAST)
Between Hospital Trauma Designation and Maternal and examination. J Ultrasound Med. 2014 Nov;33(11):2047-56.
Neonatal Outcomes after Injury among Pregnant Women in
Washington State. J Am Coll Surg. 2016 Mar;222(3):296-302. 46 Richards JR, Ormsby EL, Romo MV, Gillen MA, McGahan
JP. Blunt abdominal injury in the pregnant patient: detection
39 Brown HL. Trauma in pregnancy. Obstet Gynecol. 2009 with US. Radiology. 2004 Nov;233(2):463-70.
Jul;114(1):147-60.
47 Katz V, Balderston K, DeFreest M. Perimortem cesarean
40 Jain V, Chari R, Maslovitz S, et al. Guidelines for the delivery: were our assumptions correct? Am J Obstet
Management of a Pregnant Trauma Patient. J Obstet Gynecol. 2005 Jun;192(6):1916-20; discussion 20-1.
Gynaecol Can. 2015 Jun;37(6):553-74.
48 Katz VL. Perimortem cesarean delivery: its role in maternal
41 Blencowe H, Cousens S, Chou D, et al. Born too soon: the mortality. Semin Perinatol. 2012 Feb;36(1):68-72.
global epidemiology of 15 million preterm births. Reprod
Health. 2013;10 Suppl 1:S2. 49 McDonnell NJ. Cardiopulmonary arrest in pregnancy: two
case reports of successful outcomes in association with
42 Lawn JE, Davidge R, Paul VK, et al. Born too soon: care perimortem Caesarean delivery. Br J Anaesth. 2009 Sep;
for the preterm baby. Reprod Health. 2013;10 Suppl 1:S5. 103(3):406-9.

50 American College of O, Gynecologists. ACOG Practice
Bulletin: Clinical Management Guidelines for Obstetrician-

114

Gynecologists Number 76, October 2006: postpartum
hemorrhage. Obstet Gynecol. 2006 Oct;108(4):1039-47.

51 Haeri S, Dildy GA, 3rd. Maternal mortality from
hemorrhage. Semin Perinatol. 2012 Feb;36(1):48-55.

52 Dildy GA, Belfort MA, Adair CD, et al. Initial experience
with a dual-balloon catheter for the management of
postpartum hemorrhage. Am J Obstet Gynecol. 2014 Feb;
210(2):136 e1-6.

53 Georgiou C. Balloon tamponade in the management of
postpartum haemorrhage: a review. BJOG. 2009 May;116(6):
748-57.

54 Howard TF, Grobman WA. The relationship between timing
of postpartum hemorrhage interventions and adverse
outcomes. Am J Obstet Gynecol. 2015 Aug;213(2):239 e1-3.

55 Rufener SL, Adusumilli S, Weadock WJ, Caoili E.
Sonography of uterine abnormalities in postpartum and
postabortion patients: a potential pitfall of interpretation. J
Ultrasound Med. 2008 Mar;27(3):343-8.

56 Mulic-Lutvica A, Axelsson O. Ultrasound finding of an
echogenic mass in women with secondary postpartum
hemorrhage is associated with retained placental tissue.
Ultrasound Obstet Gynecol. 2006 Sep;28(3):312-9.

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