Ultrasound Obstet Gynecol 2010; 35: 481–485
Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/uog.7596
Transrectal ultrasound-guided surgical evacuation
of Cesarean scar ectopic pregnancy
T. BIGNARDI and G. CONDOUS
Early Pregnancy and Advanced Endosurgery Unit, Nepean Centre for Perinatal Care, Nepean Clinical School, University of Sydney, Nepean
Hospital, Penrith and OMNI Gynecological Care, Centre for Women’s Ultrasound and Early Pregnancy, St Leonard’s, Sydney, Australia
K E Y W O R D S: Cesarean scar pregnancy; ectopic pregnancy; methotrexate; transrectal ultrasound
ABSTRACT
Objectives To describe a new technique for the management of Cesarean scar ectopic pregnancy (CSEP):
transrectal ultrasound (TRS)-guided surgical evacuation.
Methods All women who presented at our early
pregnancy units (EPU) from November 2006 to July
2008 underwent transvaginal sonography. CSEP was
diagnosed if all of the following criteria were met:
absence of an intrauterine pregnancy; empty endocervical
canal; presence of a gestational sac implanted within the
lower anterior segment of the uterine corpus, with or
without evidence of myometrial thinning. Women were
offered TRS-guided surgical evacuation under general
anesthesia. Successful treatment was defined as complete
primary evacuation of the CSEP. The need to perform
additional interventions (emergency cervical cerclage,
insertion of Foley’s balloon catheter, blood transfusions)
was recorded.
Results Of 1195 consecutive women who presented at
the EPUs, seven (0.59%) were diagnosed with CSEP.
Three (43%) of these were viable at the time of diagnosis.
Two (29%) of the seven pregnancies followed in-vitro
fertilization; six (86%) women had previously had a
single Cesarean section and one had had two. One of
these women had a previous tubal ectopic pregnancy,
and one a previous CSEP. Three (43%) of the women
were asymptomatic. Five (71%) women were treated with
TRS-guided surgical evacuation as the primary treatment,
whilst two (29%) were given systemic methotrexate, one
of whom subsequently underwent TRS-guided aspiration
because of failure of conservative management. There
were no major complications.
Conclusions The best treatment for CSEP has yet to be
established. TRS-guided surgical evacuation is a novel
and potentially alternative treatment modality. However,
in the absence of further studies we cannot draw any
conclusions, and the management of such women should
be individualized. Copyright  2010 ISUOG. Published
by John Wiley & Sons, Ltd.
INTRODUCTION
A Cesarean scar ectopic pregnancy (CSEP) is a pregnancy
embedded in the myometrium of a previous Cesarean scar,
outside the uterine cavity. It is considered to be a rare form
of ectopic pregnancy, but its incidence is reported to be
as high as 1 in 1800 to 1 in 22161,2 .
A delay in diagnosis and/or treatment can lead to
uterine rupture, major hemorrhage secondary to placenta
accreta or percreta, a need for hysterectomy and serious
maternal morbidity3 – 5 . Therefore, the main objectives in
the management of CSEPs should be early and accurate
ultrasound diagnosis and prevention of severe blood loss
while preserving fertility. There is no consensus about
the method of choice for managing CSEP. The use of
blind or ultrasound-guided surgical evacuation, medical
management with methotrexate (MTX), administered
either systemically or locally, and expectant management
have all been reported in the literature, as have combined
treatments1 – 7 .
In this pilot study, we aimed to manage CSEPs surgically
using transrectal sonography (TRS)-guided surgical
evacuation of the lower anterior myometrial defect.
METHODS
This was a prospective study conducted during a 20month period, from November 2006 to July 2008, in
two ultrasound-based units, the Acute Gynaecology Unit
Correspondence to: Dr T. Bignardi, Acute Gynaecology, Early Pregnancy and Advanced Endosurgery Unit, Nepean Clinical School,
University of Sydney, Nepean Hospital, Penrith, Sydney, Australia (e-mail: [email protected])
Accepted: 5 August 2009
Copyright  2010 ISUOG. Published by John Wiley & Sons, Ltd.
ORIGINAL PAPER
482
(AGU) at Nepean Hospital and OMNI Gynaecological
Care, Centre for Women’s Ultrasound and Early
Pregnancy, both in Sydney, Australia. All pregnant women
who presented to these units during the study period
underwent transvaginal sonography (TVS) of the pelvis
by the same operator (G.C.) using a 7.5-MHz transvaginal
probe (LOGIQ-e and Voluson E8 ultrasound machines,
GE Medical Systems, Zipf, Austria). Women with a
diagnosis of CSEP were identified, the diagnosis being
made in the presence of all of the following sonographic
criteria: absence of an intrauterine pregnancy; empty
endocervical canal; presence of a gestational sac implanted
within the lower anterior segment of the uterine corpus,
with or without evidence of myometrial dehiscence
(Figure 1). Myometrial dehiscence was defined as thinning
of the myometrial layer between the bladder and the
gestational sac (Figure 2 and Videoclips S1 and S2 online).
Age, parity, symptomatology, past obstetric history and
number of previous Cesarean sections were recorded.
All women in the CSEP cohort were scheduled for
surgical management of the pregnancy. Informed consent
Figure 1 Transvaginal ultrasound imaging in two different cases of
Cesarean scar ectopic pregnancy. The gestational sac with visible
fetal pole is within the myometrial defect at the site of a previous
Cesarean section.
Copyright  2010 ISUOG. Published by John Wiley & Sons, Ltd.
Bignardi and Condous
Figure 2 Transvaginal sonographic evidence of myometrial
dehiscence in a Cesarean scar ectopic pregnancy, visualized as
thinning of the myometrium between the bladder and the
gestational sac (2.5 mm, calipers).
was given by each woman in accordance with the
hospital’s protocol. The procedure was explained to each
woman, as were the potential surgical complications,
i.e. uterine perforation and hemorrhage. As part of the
consent process we also explained in detail that in the
event of uncontrollable hemorrhage there might be a need
for emergency cervical cerclage, emergency insertion of a
Foley’s balloon catheter as a tamponade, or emergency
hysterectomy. Nepean Hospital does not have on-site
interventional radiology services and therefore the use of
uterine artery embolization as a rescue maneuver was not
possible. Each woman also had preoperative hemoglobin
and serum beta-human chorionic gonadotropin (β-hCG)
levels measured, and two units of blood were cross
matched. The anesthetic team was informed pre-emptively
about the surgical case and potential complications.
Ultrasound-guided evacuations were all performed by
the same operator (G.C.) with the woman under general
anesthesia. The cervix was grasped at the 12 o’clock
position with a vulsellum and carefully dilated up to
10 mm by the primary operator (G.C.). Intraoperative
TRS was performed under sterile conditions by a
second operator using a 7.5-MHz transvaginal probe
(LOGIQ-e). Under direct TRS guidance, a standard
suction cannula (6–8 mm) was inserted through the
cervix, beyond the endocervical canal and placed at
the level of the gestational sac, i.e. at the level of
the Cesarean section scar. The suction mechanism was
activated and the contents of the myometrial defect
removed under direct ultrasound guidance in order
to guarantee complete evacuation of the products of
conception (Videoclip S3 online). Successful treatment
was defined as complete primary evacuation of the CSEP.
The need for emergency cervical cerclage, a Foley’s
balloon catheter insertion or blood transfusion was
recorded.
Ultrasound Obstet Gynecol 2010; 35: 481–485.
Ultrasound management of CSEP
RESULTS
During the study period 1195 consecutive women
presented to the EPUs. Seven (0.59%) of these women
were diagnosed with a CSEP. One of these cases was
initially classified incorrectly as a cervical pregnancy on
ultrasound; she was given 1 mg/kg MTX intramuscularly
on days 1, 3 and 5 (baseline serum β-hCG, 48 899 IU/L)
with folinic acid rescue on days 2, 4 and 6. On review
on day 7 the β-hCG levels had failed to respond to the
high multidose MTX and the woman was rescanned. This
confirmed a twin CSEP without visible fetal poles rather
than the initial ultrasound diagnosis of cervical pregnancy.
She was immediately scheduled for TRS-guided surgical
curettage.
Table 1 summarizes the clinical data of the seven cases
with CSEP. Three of the women presented with vaginal
bleeding only, one had both lower abdominal pain (visual
analog scale score, 4) and vaginal bleeding, and three
(43%) were asymptomatic. Six (86%) of the women had
a history of a single lower segment Cesarean section and
one had two previous Cesarean sections. One woman
had a history of a tubal ectopic pregnancy, and one
had a history of a previous CSEP. Two (29%) of the
pregnancies followed in-vitro fertilization. Three (43%)
of the pregnancies were viable at the time of the initial
ultrasound diagnosis.
Five (71%) of the seven women were treated with
TRS-guided surgical evacuation as the primary treatment,
and two (29%) were administered systemic MTX. All
women treated with TRS-guided surgical evacuation had
successful resolution of the CSEP without complication.
In all cases the presence of chorionic villi in the evacuated
specimens was confirmed histologically. No woman
required emergency cervical cerclage, insertion of a Foley’s
balloon catheter or blood transfusion. Although one of
the women treated with MTX had been scheduled for
TRS-guided surgical curettage, just prior to surgery her
serum β-hCG levels were noted to have fallen in 48 h
from 7890 to 7771 IU/L and the decision to operate was
reversed (G.C.). The woman required a second dose of
MTX before successful resolution. This woman required
laparoscopic repair of a persistent myometrial defect.
DISCUSSION
Although ultrasound-guided surgical evacuation has been
described previously in the management of CSEP2,8 , this
is the first series to describe it under TRS guidance.
Regardless of the route (TVS, TRS or transabdominal),
we advocate the use of ultrasound as part of the surgical
management of these women in order to minimize the risk
of uterine perforation and retained products of conception
(RPOC). TRS enables appropriate visualization of the
entire uterine cavity and the CSEP, and simultaneously
allows more space for the movements of the suction
cannula, compared with ultrasound guidance performed
transvaginally. We believe that experience in the use of
TVS is essential before undertaking this procedure and all
Copyright  2010 ISUOG. Published by John Wiley & Sons, Ltd.
483
women must be advised of the risks of the surgery, the
most serious being hysterectomy.
The CSEP rate in our study was 7/1195 (0.59%), higher
than that in other reports1,2 . This may be explained by the
fact that our EPUs also work as tertiary referral centers
for all women with early pregnancy complications. In
our series, 43% of the CSEPs were asymptomatic. This is
consistent with the review by Rotas et al.5 including 112
CSEPs, with almost 40% of women being asymptomatic.
Usually, women with CSEP are hemodynamically stable
at presentation; however, an early uterine rupture due
to CSEP with massive hemorrhage in the first trimester
has been reported9 . In our case series, six of the seven
women with CSEP had had only one previous Cesarean
section. It seems reasonable to assume that a history of
more than one Cesarean section may increase the risk
of CSEP compared with a history of only one, but a
strong correlation between number of previous Cesarean
sections and CSEP has not yet been proven.
TVS is the tool of choice for the diagnosis of CSEP
and has an overall sensitivity of 84.6% (95% CI,
76.3–90.5%)5 . In our series the myometrial thickness
between the gestational sac and surrounding bladder
ranged from 2 to 3 mm. The addition of ultrasound is
therefore important in reducing the possibility of uterine
perforation with damage to surrounding structures. The
availability of a rapid serum β-hCG assay is crucial
when a diagnosis of CSEP is suspected, to provide a
baseline level with which to monitor the regression of the
pregnancy with treatment, especially in the case of MTX
administration.
In the absence of randomized trials, the modality of
treatment in cases of CSEP should be chosen on the
basis of gestational age, pregnancy viability, myometrial integrity, severity of symptoms, serum β-hCG levels,
the experience of the surgeon and the preference of the
woman. Treatments described1 – 7 include expectant management, operative hysteroscopy, dilatation and curettage
(D&C), ultrasound-guided evacuation, transvaginal needle aspiration, uterine artery embolization, systemic or
local MTX administration, local embryocide administration and combined approaches. Expectant management
is associated with a high risk of uterine rupture, and
therefore cannot be recommended if the pregnancy is
evolving1,7,10 ; theoretically, only those CSEPs which are
failing (i.e. with falling serum β-hCG levels) can be offered
expectant management. For evolving CSEPs (i.e. increasing serum β-hCG levels), systemic MTX can be an option
to avoid surgery under general anesthesia. However, we
believe that despite MTX being effective in normalizing
serum β-hCG levels, there is often incomplete reabsorption of the gestational sac, with ongoing irregular vaginal
bleeding. Eventually, many of these women need curettage to surgically remove the persistent gestational sac and
resolve the bleeding11 – 13 . For these reasons we believe
surgical management could be a reasonable alternative to
MTX treatment.
Ayoubi et al.8 were first to describe the technique of
US-guided evacuation of CSEP. In another series of eight
Ultrasound Obstet Gynecol 2010; 35: 481–485.
Copyright  2010 ISUOG. Published by John Wiley & Sons, Ltd.
G2, CS1
G5, CS1,
MISC2, TOP1
G6, NVD3,
CS1, MISC1
G9, NVD2,
CS1, MISC2,
TOP2, EP1
G2, CS1
41
30
46 (US)
39 (US)
44 (US)
45 (ET)
48 (ET)
41 (US)
42 (US)
GA at
diagnosis
(days)
Vaginal bleeding with
clots
Vaginal bleeding
without clots
None
Vaginal bleeding
without clots, central
pelvic pain
None
Vaginal bleeding
without clots
None
Symptoms
No
Yes
No
Yes
No
Yes
Yes
Fetal pole
Yes
No
No
Yes
No
Yes
Yes
Embryonic
cardiac
activity
112 863
8906
48 899
32 000
7890
1563
1771
β -hCG at
diagnosis
(IU/L)
TRS-guided aspiration
TRS-guided aspiration
Systemic MTX
TRS-guided aspiration
Systemic MTX
TRS-guided aspiration
TRS-guided aspiration
Treatment
None
Third dose failed,
TRS-guided
aspiration performed
None
None
Second dose
None
None
Complications
β-hCG, beta human chorionic gonadotropin; CS, Cesarean section; EP, ectopic pregnancy; ET, embryo transfer; G, gravida; GA, gestational age; MA, maternal age; MISC, miscarriage;
MTX, methotrexate; NVD, normal vaginal delivery; TOP, termination of pregnancy; TRS, transrectal sonography; US, ultrasound.
35
30
34
G3, CS1, CSEP1
G4, CS2, MISC1
23
40
Parity
MA
(years)
Table 1 Summarized clinical data in seven cases of Cesarean scar ectopic pregnancy (CSEP)
484
Bignardi and Condous
Ultrasound Obstet Gynecol 2010; 35: 481–485.
Ultrasound management of CSEP
women, the technique was successful in all cases and
there were no cases of RPOC following surgery2 . In the
most recent review on CSEPs, Rotas et al.5 concluded
that surgical evacuation is a suboptimal procedure
because three of 21 surgical cases had severe hemorrhage
that necessitated hysterectomy. However, of these three
women, one was initially misdiagnosed as incomplete
miscarriage and a blind D&C was performed1 , one was
managed with blind curettage14 , and one had already
undergone early (first-trimester) uterine rupture at the
time of presentation, due to the CSEP9 . Halperin et al.15
described a case of CSEP treated by hysterotomic wedge
resection of the entire CSEP, combined with bilateral
uterine artery ligation. We believe, however, that this
should be reserved for women with intractable bleeding
who are hemodynamically unstable, or women who are
not responding to more conservative approaches (MTX,
ultrasound-guided D&C). Transvaginal needle aspiration
has been described in only two cases of CSEP7 . In
both cases this technique was combined with the use
of local MTX administration and in one case a course
of systemic MTX had already been administered before
needle aspiration. In our cases MTX was not given in
combination with surgery. Furthermore, the authors7
commented that the remaining placenta and residual sac
structure were still detectable on ultrasound for more than
2 months after the procedure.
Although the numbers in our study are small, other
studies suggest that surgical evacuation is safe for women
who are not eligible for MTX treatment or expectant
management2,5,8 . The rate of emergency hysterectomy in
women undergoing surgical evacuation is 6%5 . The use
of ultrasound guidance during surgical evacuation may
reduce the risk of uterine perforation and the risk of
missing the gestational sac.
In conclusion, ultrasound guidance is essential for the
safe surgical management of CSEPs. There are no data to
support that one form of ultrasound-guided curettage is
superior to the other. In our series we successfully used
TRS; however, other units use transabdominal sonography. The relative rareness of CSEP means that units will
need to collaborate in the context of a multicenter trial in
order to reach any firm conclusions on the management
of these women.
485
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S U P P O R T I N G I N F O R M A T I O N ON T H E I N T E R N E T
The following supporting information may be found in the online version of this article:
Videoclip S1 Transvaginal imaging of the Cesarean scar ectopic pregnancy in Figure 2. The gestational sac with
visible fetal pole and yolk sac is within the myometrial defect at the site of a previous Cesarean section.
Videoclip S2 Transvaginal Doppler imaging of the Cesarean scar ectopic pregnancy in Figure 2. The presence of
peritrophoblastic flow suggests that the gestational sac is implanted at the site, rather than passing through the
lower uterine cavity.
Videoclip S3 Transrectal ultrasound-guided surgical evacuation of a Cesarean scar ectopic pregnancy.
Copyright  2010 ISUOG. Published by John Wiley & Sons, Ltd.
Ultrasound Obstet Gynecol 2010; 35: 481–485.