Diagnostic ultrasound ( PDFDrive )

CHAPTER 30 The First Trimester 1069
A
B
FIG. 30.27 Subchorionic Hematoma. (A) Sagittal TVS at 7 weeks’ gestation shows a small hypoechoic collection (black arrow) adjacent to
the gestational sac (white arrow). The live embryo was not in the ield of view. The bleed resolved and pregnancy continued uneventfully. (B) In
another patient, sagittal transverse TVS at 10 weeks’ gestation shows a large subacute hemorrhage (black arrow) with a lacy appearance to the
clot. A live embryo (calipers) is present. See also Video 30.5.
if normal cardiac activity is documented on a follow-up study
ater 8 weeks, the rate of subsequent irst-trimester demise remains
elevated if a slow embryonic heart rate is detected at 6 to 7
weeks. 83 Embryos with slow heart rates documented before 7.0
weeks of gestation may also be associated with an increase in
cardiac, chromosomal, and other structural anomalies. 84
Arrhythmia is also an indicator of irst-trimester loss. 85 In a
group of 950 patients, Vaccaro et al. 85 found four arrhythmias,
with three having ventricular bradycardia, all of which were
dead on follow-up scan within 2 weeks.
Embryos with abnormally rapid heart rates, above 135 bpm
before 6.3 weeks or at least 155 bpm at 6.3 to 7.0 weeks have a
good prognosis, with a high likelihood of normal outcome. 86
Subchorionic Hemorrhage
Subchorionic hemorrhage, or a hematoma resulting from elevation
of the placental margin or marginal sinus rupture, 87 causes
elevation of the chorionic membrane (Fig. 30.27, Video 30.5).
Acute hemorrhage is usually hyperechoic or isoechoic relative
to the decidua. he hemorrhage gradually becomes sonolucent
in 1 to 2 weeks.
his inding may be associated with vaginal bleeding. he
incidence of subchorionic hematomas early in pregnancy ranges
from 1.3% to 18%. 88 he association of subchorionic hematomas
with early pregnancy failure is variable, but most studies support
that worse outcomes are seen in “large” hematomas extending
50% or more of the circumference of the gestational sac and in
hematomas diagnosed earlier in the irst trimester (Fig. 30.27B).
Pedersen and Mantoni 89 studied 342 pregnant women from
9 to 20 weeks’ gestation presenting with vaginal bleeding and
found subchorionic hematomas in 18%, averaging 20 mL (range,
2-150) in size. his study found no diference in the rate of
miscarriage (10%) or premature delivery (11%) between the
patients with and without subchorionic hematomas.
In a retrospective study of 516 patients with irst-trimester
bleeding, Bennett et al. 90 found an overall pregnancy loss rate
of 9.3%. Pregnancy loss increased with increasing maternal age
and decreasing gestational age. For women over age 35, the rate
is 13.8% (vs. 7.3 for those younger than 35 years), and for those
presenting at or before 8 weeks, it is 13.7% (vs. only 5.9% for
those later in gestation). he most important predictor for
pregnancy loss was the presence of a large subchorionic hemorrhage.
90 he small or medium-sized hemorrhages (i.e., ≤50% the
sac circumference) had a miscarriage rate of 9%, versus 18.8%
for the larger subchorionic hemorrhages. In a study involving
patients from 5 to 14 weeks’ gestation, Leite et al. found that
patients with very large hematomas were associated with adverse
outcome in 46% of pregnancies. In their study, vaginal bleeding
was not associated with a poor prognosis, but diagnosis at early
gestational age was associated with a worse outcome. 91
ECTOPIC PREGNANCY
Ectopic pregnancy remains one of the leading causes of maternal
death in the United States. It accounts for 1.4% of all pregnancies
and approximately 15% of maternal deaths. Although the
incidence of ectopic pregnancy is increasing, the mortality rate
has declined to less than 1 in 1000 cases compared with 3.5 in
1000 in 1970. 92,93 he increased incidence is likely caused by
increased prevalence of the risk factors as well as earlier diagnosis,
whereas heightened awareness and improved diagnostic capabilities
have led to a decrease in the mortality rate.
Clinical Presentation
he classic clinical triad of pain, abnormal vaginal bleeding, and
a palpable adnexal mass is present in approximately 45% of
patients with ectopic pregnancy. 94 In addition, the positive predictive
value of this triad is only 14%. Other presenting signs and
symptoms include any combination of the classic triad, as well
as amenorrhea, adnexal tenderness, and cervical motion tenderness.
Schwartz and Di Pietro 94 found that only 9% of patients
with clinically suspected ectopic pregnancy actually had an ectopic
pregnancy, whereas 17% had symptomatic ovarian cysts, 13%
had pelvic inlammatory disease, 8% had dysfunctional uterine