Scar ectopic pregnancy

Dr. Alka Pandey
MD, Ph.D.,
Associate Professor, P.M.C.H., Patna

 Scar pregnancy is an ectopic pregnancy
implanted in the myometrium at the site of a
previous CS Scar.
 It was first described in 1978 by Larsen and
Soloman.

Prevalence
 Prevalence of CSP is increasing and to date
more than 1000 cases have been reported.
 This may be attributed to :
○ Increasing Number of CS
○ Increasing awareness
○ Better diagnostic technique

Risk Factors
 May occur after any myometrial trauma -
 Caesarean Section
 Manual Removal of placenta
 Myomectomy
 D & C

Pathophysiology
 Endometrial and myometrial disruption of scar are
predisposing factors.
 Invasion by the implanting blastocyst through a
microscopic tract that develops from the trauma of
an earlier CS.
 The risk of scar implantation might be proportional to
the size of the anterior uterine wall defect.
 Caesarean section for a breech presentation in a
previous pregnancy appears to be most frequently at
risk of future CSP.

Pathophysiology
 May be secondary to :
○ Systemic diseases – DM (Poor blood flow)
○ Poor tissue quality -
 Inadequate collagen formation
 Post operative wound infection
 Short interval pregnancy
○ Improper closure

Diagnosis
 History of amenorrhoea followed by bleeding.
 Positive pregnancy test
 Trans vaginal ultrasound

Diagnosis
○ Ultrasound criteria : -
 Empty uterine cavity , closed and empty cervical canal
 Placenta and/or a gestational sac embedded in the scar of a
previous caesarean section
 A triangular/round or oval‐shaped gestational sac that fills the
niche of the scar
 A thin or absent myometrial layer between the gestational sac
and the bladder
 Yolk sac, embryo and cardiac activity may or may not be
present
 Evidence of functional trophoblastic/placental circulation on
colour flow Doppler examination, characterised by high
velocity and low impedance blood flow
 Negative ‘sliding organs’ sign

Diagnosis
 Trans abdominal pelvic ultrasound is particularly
useful in later gestation when a trans vaginal scan
may not provide panoramic view.

Diagnosis
 TVS 3D ultrasound with Power Doppler
identifies peritrophoblastic vascular flow in
the tissue surrounding the sac and
measurement of the myometrial thickness
is relatively easier.

Diagnosis
 MRI is also a useful adjunct.

Naked eye / laparoscopic picture

Classification
 Type-1 or endogenic – where implantation
occurs on the scar and the gestational sac
grows towards the cervico isthmic or uterine
cavity.
 Type-2 or exogenic – CSP occurs when the
gestional sac is deeply embedded in the
scar and the surrounding myometrium and
grows towards the bladder.

Types of Scar Ectopic Pregnancy

Classification
 The myometrial layer between the
gestational sac and the bladder becomes
very thin and may disappear with bulging of
the gestational sac through the gap as the
pregnancy advances.
 In two – third of the cases the thickness of
the scar may be less than 5 mm.

Clinical Presentation
 Asymptomatic – 37%
 Painless vaginal bleeding – 39%
 Generalized abdominal pain – 25%

Differential Diagnosis
 Inevitable miscarriage with a low lying sac –
○ In an impending miscarriage the gestational
sac is often irregular and located within the
uterine cavity with absent or minimal colour
Doppler flow.
○ Gentle pressure at the level of the internal os
may displace the gestational sac – sliding
sign.

Differential Diagnosis
 Cervical ectopic pregnancy –
○ Present in or close to the cervical canal
with ballooning of the cervix.
○ Good colour flow Doppler and a
negative sliding sign.

Risk factors influencing management
choices
Management
 Patient factors
 Symptoms
 Fertility wishes
 Acceptability of prolonged follow up
 Associated lesions
 Surgical risk factors
 Response to initial treatment

Management
 Caesarean scar pregnancy (CSP)
 Gestational age
 Human chorionic gonadotropin (hCG) levels
 Size of CSP mass
 Type of CSP
 Myometrial thickness
 Viability
 Facilities
 Interventional radiology
 Surgical expertise/facilities
 Monitoring facilities

Management
 No consensus on the preferred mode of treatment.
 All treatment options carry a risk of haemorrhage
and subsequent hysterectomy.
 Treatment should be individualized based on full
pre-treatment evaluation.
 Pregnancy should be ended as soon as possible
after confirming the diagnosis.

Management
 Expectant management –
 Used very rarely in selected cases
 Patient must be in stable condition and
thoroughly counseled.
 Close monitoring
 Minimal symptoms
 Compliant
 Type – 1 CSP
 Declining beta HCG
 No fetal cardiac activity

Management
 Medical management –
 Candidates –
○ Less than 8 weeks pregnancy
○ Absent fetal cardiac activity
○ Stable
○ Beta HCG <5000 – 12000 IU
○ Myometrial thickness between bladder and
gestation sac >2 mm
 Systemic methotrexate
○ Single dose 1 mg/kg or 50 mg/cm
2
IM at an
interval of 2 or 3 days three or four doses.

Management
 Local injection and embolisation –
 Local injection of methotrexate with sac
aspiration
 Local injection of other embryocides

Management
 Surgical management
 Dilatation and surgical evacuation
 Hysteroscopic resection
 Vaginal excision and resuturing
 Laparoscopic excision and resuturing
 Open excision and resuturing
 Combined laparoscopic and hysteroscopic
procedure
 Combined laparoscopic and vaginal surgery
 Hysterectomy

Management
 Combined or sequential management –
 Uterine artery embolisation/chemoembolisation
followed by dilatation and evacuation/surgical
resection in 24–48 hours
 Methotrexate followed by surgical evacuation or
resection after an interval

 Intrauterine Balloon Catheter – can be
used successfully to compress the
gestational sac.
 Catheter is left for 48 hours
 Antibiotics given
 Outer end of the catheter is fastened to
the thigh.

Prevention
 Avoid pregnancy 12 to 24 months.
 Surgical repair of uterine scar defects
with single or double layer closure.

Summary
 CSP is an uncommon but potentially life-
threatening condition.

 The incidence is rising as CSR is rising.
 Precursor of morbidly adherent placenta.
 Do not confuse CSP with ectopic pregnancy.
 Early diagnosis is important. TVS is the most
effective and preferred diagnostic tool.
 Determine whether heart activity is present.

Summary
 If heart activity is documented: Counsel the patient.
 Inform the patient of the risks of pregnancy
continuation.
 If continuation: an additional counseling session:
risks should be explained.
 If termination: a reliable treatment that stops fetal
heart beat without delay.

Summary
 Avoid single treatments as they are unlikely to be
effective:
 D&C
 Suction curettage
 Single-dose IM MTX, and UAE
 Removal of Scar ectopic by any of the following
(Hysteroscopy, Laparoscopy, Laparatomy, Vaginally)
and resuturing of the scar

Summary
 Consider combination treatments: best results.
direct injection of MTX or Kcl into GS with TVS
guidance.
 In a future pregnancy, an early visit for TVS is
important.

Complications
 Placenta previa/accreta
 Uterine rupture
 Massive Haemorrhage : increased
maternal morbidity and mortality.

Scar ectopic pregnancy

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