Original post, lightly edited for flow:
One of our OBs is interested in uterine artery embolization as part of a treatment pathway for cesarean scar pregnancy. On my review, there is good bit of international experience and published studies/protocols out there, but a paucity of published U.S. experience. I’m curious if anyone has experience with this and/or an established pathway at their institution that employs embolization in certain cases.
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Transvaginal US images obtained approximately 3-months post direct injection of methotrexate into the gestational sac showed a normal sized anteverted uterus. There was a fluid filled structure present at the anterior utero-cervical junction measuring 1.8 x 1.5 x 1.8 cm at the site of the cesarean scar pregnancy consistent with a residual gestational sac. No internal contents visualized. No vascularity apparent.
Author name
Brian James Strife, MD
Assistant Professor
Division of Vascular and Interventional Radiology
Department of Radiology
Virginia Commonwealth University Health System
In your own words, what is an accepted definition for cesarean section scar ectopic pregnancy?
Brian James Strife, MD: Cesarean scan pregnancy (CSP) is a type of ectopic pregnancy whereby the embryo implants in a previous cesarean scar. The position of the implantation along the scar track further subclassifies the CSP into different types with potentially different treatments offered for each type.
Please elaborate on the specific patient background and presentation in this case.
The patient is in her mid-30s with a history of two prior deliveries by cesarean section. She unexpectedly became pregnant, and ultrasound demonstrated a cesarean scar ectopic pregnancy at just over 5 weeks gestational age. She was advised of the risks from this type of pregnancy and that termination was warranted. She underwent ultrasound-guided methotrexate injection into the gestational sac by her referring obstetrician with subsequent appropriate decline in the B hCG levels. Despite a successful termination procedure, she experienced intermittent heavy bleeding with symptomatic anemia and was referred for uterine artery embolization (UAE). Follow-up ultrasound was notable for a residual gestational sac only and no abnormal vascularity. Her bleeding stopped a few weeks after termination and has not recurred.
In your opinion, what role can IR play in cases of ectopic uterine scar pregnancy (primary vs. secondary intervention in conjunction with medical/surgical treatment)?
For CSP, a rare type of ectopic pregnancy, there are several ways an IR may become involved in the patient’s care. UAE can be the primary termination procedure, commonly performed using bilateral embolization with an embolic mixed with methotrexate. Or UAE may be employed as a hybrid procedure along with evacuation. In the hybrid procedure, UAE is performed to treat the abnormal vascularity associated with the ectopic implantation followed by obstetric evacuation in the following 2–3 days. As in this case, there are other opportunities to consider UAE whereby persistent abnormal uterine bleeding occurred despite successful pregnancy termination.
For which cases do you typically perform prophylactic UAE? Do you have experience with embolization in the setting of CSP?
I don’t do much prophylactic embolization. My practice involves treating women with symptomatic fibroids, adenomyosis and rarely uterine arteriovenous malformations. I also perform UAE in cases of postpartum hemorrhage and bleeding associated with abnormal placental implantation. This was my first referral for UAE in the setting of a CSP.
What specifically prompted you to reach out regarding this case/topic?
Despite practicing for over 10 years at a large academic urban medical center, I had never been approached to intervene on a patient with a CSP. Admittedly, I was completely naive to the potential roles an IR physician may play in the care of these patients.
Is there a role for collaboration with OB/Gyn in these cases?
Definitely. In my experience, it’s helpful to proactively develop a multidisciplinary management pathway for these uncommon scenarios to prevent recreating the wheel each time they occur. Creating the pathway forces you to examine the published experience and learn from it, but also encourages collaboration with another specialty which is often mutually beneficial.
What post or posts were most valuable to you and why?
I received a number of replies and direct messages that were helpful. First, it was clear this was uncommon in practice, as few operators had more than a few cases of experience. Second, the role of the IR physician varied from performing the primary procedure to utilizing the hybrid approach to even performing microwave ablation. This was congruent with the published literature whereby some authors favored one approach over another without a clear definitive practice guideline or role for IR procedures.
Will you or have you changed your practice patterns based off of responses on SIR Connect? Please describe any changes you are considering.
I am currently working with the referring obstetrician to establish a local pathway or guideline with the goal of involving the IR team at various steps depending on what is needed for the patient. I will reach out to some of our members who responded to my inquiry to hear more about their experiences, pearls and pitfalls.
Additional comments:
Cesarean scar pregnancy (CSP) is a rare ectopic pregnancy in which the embryo implants in a previous cesarean scar. This can lead to complications such as uterine rupture and profuse bleeding as pregnancy progresses, posing significant risk to maternal and fetal health as well as future fertility.1,2 As the number of C-sections continues to increase worldwide, so does the incidence of CSP. CSP occurs in approximately 1 in 2,000 pregnancies and accounts for 6% of abnormally implanted pregnancies among patients with a prior cesarean birth.3 The diagnosis of CSP is most often made on first trimester transvaginal ultrasound, which has been found to be the superior imaging modality when compared to transabdominal. Imaging findings often include an empty uterus and cervical canal with development of the gestational sac in the anterior lower uterine segment at site of cesarean scar.1 The Society for Maternal-Fetal Medicine describes surgical, medical and minimally invasive therapies for CSP management, but the optimal treatment strategy is not yet known.4 Systematic reviews have suggested that overall surgical interventions have been associated with higher rates of success and pregnancy resolution (83%) when compared to medical treatment alone (60%).5
Some of the current treatment strategies established for CSP include: systemic MTX plus curettage, embryo aspiration plus local administration of MTX, uterine artery embolization (UAE) followed by curettage, UAE as primary termination procedure and surgical removal of the CSP either transvaginally, laparoscopically or assisted by hysteroscopy.6,7 The role of IRs in treatment is not clearly defined by clinical guidelines. However, treatment most commonly involves UAE as adjuvant to treat abnormal uterine vascularity in combination with an evacuation procedure (i.e., UAE plus dilatation and curettage [D&C]), UAE as primary termination procedure or for persistent bleeding after primary termination procedure such as described in the case above.7
In a 2009 prospective controlled trial published in the American Journal of Obstetrics and Gynecology, 72 women with CSP were randomized to UAE or systemic methotrexate (MTX) group, all of which underwent suction curettage 24 hours later. Results of the study showed that, compared to MTX, patients who underwent UAE showed a significant decrease in bleeding volumes (P < .001), shorter hospitalization stay, lower hysterectomy rate and no differences in severe side effects.8 Furthermore, a recent retrospective study (Wang et al. 2021) demonstrated that shorter interval treatments between UAE with gelfoam and suction aspiration were found to decrease hemorrhage. Rates of intraoperative bleeding were 5% for patients who received curettage within 24 hours after UAE and 19.4% for those who had a treatment interval longer than 72 hours with an adjusted odds ratio of 3.37 (95% confidence interval: 1.40–8.09).9 In a study of 66 women with CSP who were given the choice of treatment (Yang et al. 2010), 38 elected to receive bilateral UAE with gelatin sponge particles and local MTX administration, 11 chose D&C and 17 chose systemic MTX. Successful outcomes were measured and defined as a complete recovery with no severe complications and with the preservation of fertility. The success rate was significantly higher in the UAE group (89.5%) compared to the systemic MTX (27.3%) or D&C groups (58.8%; P < 0.001). Additionally, the mean blood loss, time for B-HCG decline and hospital stay were all significantly lower in the UAE group. Authors concluded that UAE combined with local MTX is a safe and effective primary treatment strategy for CSP. It should be noted, however, that 63% of patients in the UAE group required additional curettage due to persistent embryo mass or persistent bleeding on an average of five days post procedure. Unsurprisingly, the rate of massive bleeding after curettage was reduced in the women previously treated with UAE (16.7%) compared to those who received only curettage as the primary treatment (72.7%).10
In summary, it is clear that UAE has a role in the treatment of CSP with the main clinical objective to prevent massive blood loss and maintain the patient’s fertility and quality of life. Due to relatively low incidence of CSP, there are currently no universal management guidelines. The choice of treatment modality is often guided by the type of CSP, gestational age, vascularity, hemodynamic stability, medical expertise, patient preference and equipment/personnel availability.
References:
- Rotas MA, Haberman S, Levgur M. Cesarean scar ectopic pregnancies: etiology, diagnosis, and management. Obstet Gynecol. 2006 Jun;107(6):1373-81. doi: 10.1097/01.AOG.0000218690.24494.ce. PMID: 16738166.
- Silver RM. Implications of the first cesarean: perinatal and future reproductive health and subsequent cesareans, placentation issues, uterine rupture risk, morbidity, and mortality. Semin Perinatol 2012;36:315–23. VOL. 105 NO. 4/APRIL 2016: 965.
- Liou N, Mallick R, Odejinmi F. From laparotomy to laparoscopy for all. Current trends in the surgical management of ectopic pregnancies: a prospective analysis of over 1000 cases. BJOG An Int J Obstet Gynaecol 2018; 3:175–177.
- Society for Maternal-Fetal Medicine (SMFM). Electronic address: pubs@smfm.org. Miller R, Timor-Tritsch IE, Gyamfi-Bannerman C. Society for Maternal-Fetal Medicine (SMFM) Consult Series #49: Cesarean scar pregnancy. Am J Obstet Gynecol 2020; 222:B2–B14.
- Maheux-Lacroix S, Li F, Bujold E, Nesbitt-Hawes E, Deans R, Abbott J. Cesarean Scar Pregnancies: A Systematic Review of Treatment Options. J Minim Invasive Gynecol. 2017 Sep-Oct;24(6):915-925. doi: 10.1016/j.jmig.2017.05.019. Epub 2017 Jul 18. PMID: 28599886.
- Birch Petersen K, Hoffmann E, Rifbjerg Larsen C, Svarre Nielsen H. Cesarean scar pregnancy: a systematic review of treatment studies. Fertil Steril. 2016 Apr;105(4):958-67. doi: 10.1016/j.fertnstert.2015.12.130. Epub 2016 Jan 18. PMID: 26794422.
- Litwicka K, Greco E. Caesarean scar pregnancy: a review of management options. Curr Opin Obstet Gynecol. 2011 Dec;23(6):415-21. doi: 10.1097/GCO.0b013e32834cef0c. PMID: 22011956.
- Zhuang Y, Huang L. Uterine artery embolization compared with methotrexate for the management of pregnancy implanted within a cesarean scar. Am J Obstet Gynecol. 2009 Aug;201(2):152.e1-3. doi: 10.1016/j.ajog.2009.04.038. Epub 2009 Jun 13. PMID: 19527897.
- Wang Q, Peng H, Zhao X, Qi X. When to perform curettage after uterine artery embolization for cesarean scar pregnancy: a clinical study. BMC Pregnancy Childbirth. 2021 May 10;21(1):367. doi: 10.1186/s12884-021-03846-x. PMID: 33971838; PMCID: PMC8108320.
- Yang XY, Yu H, Li KM, Chu YX, Zheng A. Uterine artery embolisation combined with local methotrexate for treatment of caesarean scar pregnancy. BJOG. 2010 Jul;117(8):990-6. doi: 10.1111/j.1471-0528.2010.02578.x. PMID: 20536432.
Disclaimer: This column represents the work and opinions of the contributing authors and do not necessarily reflect the views or policies of SIR. SIR assumes no liability, legal, financial or otherwise, for the accuracy of information in this article or the manner in which it is used. The statements made in the column are not intended to set a standard of care and should not be treated as medical advice nor as a substitute for independent, professional judgment. Please note: Due to recent law changes, certain procedures detailed within this article may not be legally permitted in your state. Please be sure to confer with your institution’s legal advisers.
