Diagnostic ultrasound ( PDFDrive )

1070 PART IV Obstetric and Fetal Sonography
bleeding, and 7% had spontaneous abortions. he clinical presentation
is thus nonspeciic. In addition, even in retrospect,
8.7% of proven ectopic pregnancies are sonographically normal
at the time of initial evaluation. 95
he prevalence of ectopic pregnancy varies according to the
patient population and their inherent risk factors. Nevertheless,
all patients in the reproductive age group are at risk. Factors that
increase the risk of ectopic pregnancy include tubal abnormality
preventing passage of the zygote or resulting in delayed transit;
previous ectopic pregnancy, 96,97 cesarean section, or tubal reconstructive
surgery; pelvic inlammatory disease; chlamydial salpingitis
98 ; intrauterine contraceptive devices; and increased age
or parity.
here is an association between infertility and ectopic
pregnancy, likely because of the shared tubal abnormalities in
both conditions. he risk factors for ectopic pregnancy are therefore
present in patients who undergo ovulation induction or IVF and
embryo transfer. he increased incidence of multiple pregnancies
with ovulation induction and IVF further increases the risk for
both ectopic and heterotopic (coexistent intrauterine and ectopic)
gestation. he hydrostatic forces generated during embryo transfer
may also contribute to the increased risk. 99 he frequency of
heterotopic pregnancy was originally estimated on a theoretic
basis to be 1 in 30,000 pregnancies. More recent data indicate
that the rate is approximately 1 in 7000 pregnancies. 100,101
Risk of Ectopic Pregnancy
Any tubal abnormality that may prevent passage of zygote
or result in delayed transit
Previous tubal pregnancy
History of tubal reconstructive surgery
Pelvic inlammatory disease
Intrauterine contraceptive device
Increased maternal age
Increased parity
Previous cesarean section
Sonographic Diagnosis
Because any woman of child-bearing age is at risk for ectopic
pregnancy, determining the location of a pregnancy is required
for any pregnant woman who has a pelvic ultrasound. he differential
diagnosis for pelvic pain in early pregnancy is vast,
including ectopic pregnancy, early pregnancy failure, tubo-ovarian
torsion, degenerating ibroids, and ovarian cysts.
A limited TAS is recommended in all cases of suspected ectopic
pregnancy in which the TVS does not provide a clear diagnosis,
looking for indings that may be outside the range of the transvaginal
probe. Although a full bladder is preferred, in the emergent
setting patients should not be required to ill their bladder prior
to imaging. 102 he TAS exam should include views of the uterus
and adnexa in the sagittal and transverse orientations. When
luid is seen in the pelvis, it is helpful to look higher in the
abdomen for the extent of luid to provide a sense of the degree
of blood loss. With a large volume of blood loss, the patient
could decompensate rapidly. Fluid seen in the upper abdomen
should impart a greater sense of urgency to the clinical setting
(Figs. 30.28 and 30.29).
TVS assessment of the uterus, ovaries, and adnexal regions
should almost always be performed, as it is superior to TAS in
evaluating the endometrial contents and adnexa, providing a
diagnosis more oten and earlier. Views of the uterus in the
sagittal and transverse planes should be performed to assess for
a small gestational sac. he adnexa should be imaged with
documentation of the ovaries as well as the space between the
ovaries and uterus as this is the most common location of an
ectopic adnexal mass. 103 During the TVS, it may be helpful to
perform a gentle bimanual examination with the probe and a
hand providing gentle pressure to move a questionable mass
away from the ovary. If the mass moves separately from the
ovary (Video 30.6), it is more likely to be an ectopic mass rather
than an ovarian mass, most commonly a corpus luteal cyst. A
suspected ectopic mass should be assessed during the TVS for
local tenderness. he probe is used to apply light pressure on
the mass. his pressure almost always elicits pain similar to the
A
B
FIG. 30.28 Live Ectopic Pregnancy. A 33-year-old woman with left lower quadrant pain at 9 weeks’ gestation. (A) Transverse TAS of the right
adnexa shows a gestational sac with an embryo. Cardiac activity was seen at real-time imaging. (B) TVS shows the uterus (white arrows) and
some clot in the cul-de-sac (black arrow). However, the ectopic pregnancy was only seen on the TAS.