Ectopic Pregnancy: A Clinical Casebook

14. Cesarean Scar Pregnancy

Marcos Cordoba Ana Monteagudo1 and Ilan E. Timor-Tritsch1


Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, New York University School of Medicine, 10016 New York, NY, USA

Marcos Cordoba



Cesarean scar pregnancyCesarean ectopicCesarean section scar pregnancy

Case Study

A 41-year-old G5P4004 presented to the emergency department complaining of vaginal spotting for 2 days. The patient had a history of three prior cesarean deliveries (CDs). By dates she was 5 weeks and 2 days. The initial transvaginal ultrasound (TVUS) by the resident showed a gestational sac with a yolk sac embedded in the anterior uterine wall in the cesarean scar (Fig. 14.1a).


Fig. 14.1

Cesarean scar pregnancy before the injection: a Gestational sac (GS) with a yolk sac (arrow) embedded in the low, anterior uterine wall. b 3-mm myometrial layer between the GS and the bladder. The arrow points to the GS. c CRL of 5.5 mm consistent with a 6 2/7 days pregnancy. d Transvaginal intragestational sac injection (arrow) points to the needle. Cx = cervix. Crown–rump length (CRL)

A 3-mm myometrial layer was measured between the sac and the bladder (Fig. 14.1b). No embryonic pole or heartbeat was seen and the cervix appeared normal. The serum human chorionic hormone (hCG) was 2900 mIU/mL. These findings were consistent with a cesarean scar pregnancy (CSP) .

My Management






Diagnosis and Assessment

Many obstetrics and gynecology (OB/GYN) practitioners have never diagnosed or treated a patient with a CSP . Those who did, faced a management problem. Over the past few decades, the prevalence of CDs has increased. This raise in the USA reached 60 % from 1996 to 2009 [1]. Currently, the CD rate has stabilized to 31.3 % [2]. Among the many complications of CDs, the least known is CSP, which may become a life-threatening condition [3].

CSP is defined as an abnormal implantation of a gestational sac in the niche created by the incision site of the previous CD, below or on the thin myometrium and the fibrous tissue of a previous cesarean scar in the presence of an empty uterine cavity and cervical canal. It has an estimated incidence of 1/1800–1/2500 of all CDs [4].

The diagnosis of CSP requires a high clinical index of suspicion. When evaluating patients with CSP, two main differential diagnoses should be considered: cervical pregnancy and spontaneous miscarriage in progress. The former is most likely to occur in patients with no history of previous CD. In the latter, the abortion sac happened to be “caught” passing the cervix and does not demonstrate a live embryo/fetus.

The diagnosis of CSP is based upon:






As a rule, if a low, anteriorly located gestational sac is seen in a patient with a previous CD, it should be considered as a CSP . Treatment options can be classified into two groups: surgical or minimally invasive. Surgical treatment requires general anesthesia. They include: dilation and curettage (D&C), excision by hysteroscopy, laparoscopy, or laparotomy. Minimally invasive interventions include: local and/or systemic injection of MTX or KCl. Other procedures include UAE. Lately, insertion and inflation of a Foley balloon catheter, as an adjuvant to other treatments, has also been used to prevent or to tamponade bleeding from the pregnancy site.

After the diagnosis is established, the patient should be counseled about the management. This should be personalized, taking into account the patient’s age, number of children, number of previous CDs, the patient’s expectations as well as the provider’s experience [56].


Treatment of complications of the cases reviewed in the literature occurred mostly with the use of single treatments such as systemic administration of MTX, after D&C, and following UAE. Below is a short account of the most used treatments and treatment combinations [4].

Systemic, Single-Dose MTX

The dose is usually 1 mg/kg body weight or 50 mg/m2 body surface. Reviewing the literature, this resulted in 64.6 % complication rate [3], mainly because it required a secondary treatment, since the pregnancy continued and the embryonic cardiac activity did not cease even after several days. Waiting for the drug effect, the gestational sac, the embryo/fetus, and its vascularity are growing. A secondary treatment had to deal with a larger gestation, a more abundant vascularization, and thus with a potentially increased risk of complications.

Systemic, Multidose, Sequential MTX Treatment

This treatment includes several consecutive doses of those of the “one dose” regimen administered every 2 or 3 days over 1 week. One should be aware of its cumulative side effects on the liver and bone marrow. Even such treatment fails at times.

Transabdominal or Transvaginal US-Guided Local, Intragestational Sac Injection of MTX/ KCI

No anesthesia is required. Intragestational sac injections had the lower rates of complications (10.8 %). Usually 50–75 mg MTX is the dose used. This treatment was associated with the lowest complication rate [4].

Suction Aspiration and/or D&C Alone or in Combination

Requires general anesthesia. The 305 cases reviewed in the literature resulted in about 62 % (29–86 %) complications, most of them as a result of profuse bleeding since the area of implantation has no muscular mechanism and the ability to occlude bleeding vessels different to the muscular mechanism in the body of the uterus [3]. If D&C or an aspiration is still an option, consider having blood products and a Foley balloon catheter to be available.

Uterine Artery Embolization Alone or in Combination

Requires general anesthesia. Up to 47 % complication rate was reported [3]. Waiting for its effect it allows the gestation to grow and its vascularity to increase. In the event of its failure, a larger pregnancy has to be dealt with it and may be appropriate an adjuvant therapy.

Excision by Laparotomy Alone or in Combination with Hysteroscopy

Excision by laparotomy, laparoscopy, or hysteroscopy requires general anesthesia and many have complications rates of 30–85 % respectively.

The Adjuvant Use of a Foley Balloon Catheter

Insertion of a Foley balloon catheter and inflating it at the site of the CSP to prevent or to treat bleeding by its tamponing effect is a new supplement to several treatment options.


Fifty milligrams of systemic MTX was injected and a follow-up in 5–7 days at her gynecologist was suggested. Seven days later, an embryo with a CRL of 5.5 mm with positive heartbeats was seen within the gestational sac (Fig. 14.1c). The decision was to perform a transvaginal intragestational sac injection of 50 mg of MTX using a 22-gauge needle under real-time TVUS guidance (Fig. 14.1d). Another 50 mg were injected IM. The heartbeats stopped; however, scant vaginal bleeding was noted and the vascularity around the sac appeared significant (Fig. 14.2a).


Fig. 14.2

Cesarean scar pregnancy (CSP) after the intragestational sac injection: a Significant vascularity (arrow) surrounding the CSP , b Foley balloon catheter inserted into the uterine cavity under ultrasound guidance, c Increased blood flow around the CSP (arrow), d Prominent vascularity with PSV measuring 90 cm/s consistent with AVM. peak systolic velocity (PSV), arteriovenous malformation (AVM) (arrow)

A Foley balloon catheter was inserted and inflated with 10 ml of saline and was left in place (Fig. 14.2b). After controlling the vaginal bleeding, the patient was discharged home. The serum (hCG) on the day of the sac injection was 10,618 IU/mL.

The balloon catheter spontaneously slipped out 2 days after its placement; however, minimal vaginal bleeding was noted. Eight weeks after the procedure, TVUS still revealed the involuted pregnancy in the anterior lower segment of the uterus with abundant blood flow around it by Doppler interrogation (Fig. 14.2c). The peak systolic velocity (PSV) was 60 cm/s. Two weeks later, the vascularity became even more prominent with the PSV measuring 90 cm/s. This clinical and sonographic picture was consistent with an arteriovenous malformation (AVM) (Fig. 14.2d). The patient was consented for a uterine artery embolization (UAE) which was successfully performed 2 weeks later after which the area of vascularity diminished significantly. In 2 additional weeks, the area appeared healed.

Clinical Pearls/Pitfalls

·               TVUS is imperative for early diagnosis. Delay in the diagnosis compromise treatment.

·               In a patient with previous CD, a low, anterior chorionic sac is almost always a CSP.

·               Determine the presence or absence of heart activity.

·               The use of MTX is rarely indicated if no heart activity is seen.

·               If heart activity is seen, provide evidence-based counseling about options available to the patient.

·               If continuation of the pregnancy is desired, provide evidence-based counseling as to the outcome and discuss the possibility of developing a morbidly adherent placenta with its consequences.

·               If continuation of the pregnancy is not desired, provide an immediate and effective treatment that stops the heartbeat without delay.

·               Early treatment minimizes complications.

·               D&C, suction curettage, single-dose IM, MTX, and UAE applied alone as single treatments should be avoided if possible.

·               Foley balloon tamponade to prevent or treat bleeding should be kept in mind and at easy reach when needed.

·               Combination treatments may provide the best results. If the patient desires to continue the pregnancy, provide an additional counseling session in which a more detailed overview of the anticipated clinical road is well understood.



Häger RME, Daltveit AK, Hofoss D, Nilsen ST, Kolaas T, Øian P, et al. Complications of cesarean deliveries: Rates and risk factors. Am J Obstet Gynecol. 2004;190(2):428–34.CrossRefPubMed


Hamilton BE, Martin JA, Ventura SJ. Births: preliminary data for 2012. Natl Vital Stat Rep. 2013;62(3):1–20.


Timor-Tritsch IE, Monteagudo A. Unforeseen consequences of the increasing rate of cesarean deliveries: early placenta accreta and cesarean scar pregnancy. A review. Am J Obstet Gynecol. 2012;207(1):14–29.CrossRefPubMed


Timor-Tritsch IE, Monteagudo A, Santos R, Tsymbal T, Pineda G, Arslan AA. The diagnosis, treatment, and follow-up of cesarean scar pregnancy. Am J Obstet Gynecol. 2012;207(1):44.e1–13.CrossRefPubMed


Ballas J, Pretorius D, Hull AD, Resnik R, Ramos GA. Identifying sonographic markers for placenta accreta in the first trimester. J Ultrasound Med. 2012;31(11):1835–41.PubMed


Timor-Tritsch IE, Monteagudo A, Calì G, Palacios-Jaraquemada JM, Maymon R, Arslan AA, et al. Cesarean scar pregnancy and early placenta accreta share a common histology. Ultrasound Obstet Gynecol. 2014;43(4):383–95.CrossRefPubMed