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Cesarean scar pregnancy (CSP) is a complication in which an early pregnancy implants in the scar from a prior cesarean delivery. Incidence and recognition of this condition appear to have increased over the past two decades, perhaps due to high worldwide cesarean delivery rates. The clinical presentation is variable, and many women are asymptomatic at presentation. CSP can be difficult to diagnose in a timely fashion. Ultrasound is the primary imaging modality for CSP diagnosis.

Expectantly managed CSP is associated with high rates of severe maternal morbidity such as hemorrhage, placenta accreta spectrum (PAS), and uterine rupture. Given these substantial risks, pregnancy termination is recommended after CSP diagnosis. Several surgical and medical treatments have been described for this disorder, but at this time, optimal management remains uncertain. 

The Society for Maternal-Fetal Medicine Consult series #49 on cesarean scar pregnancy: Summary of Recommendations

Cesarean scar pregnancy (CSP) is a complication in which an early pregnancy implants in the scar from a prior cesarean delivery. Incidence and recognition of this condition appear to have increased over the past two decades, perhaps due to high worldwide cesarean delivery rates. The clinical presentation is variable, and many women are asymptomatic at presentation. CSP can be difficult to diagnose in a timely fashion. Ultrasound is the primary imaging modality for CSP diagnosis. Expectantly managed CSP is associated with high rates of severe maternal morbidity such as hemorrhage, placenta accreta spectrum (PAS), and uterine rupture. Given these substantial risks, pregnancy termination is recommended after CSP diagnosis. Several surgical and medical treatments have been described for this disorder, but at this time, optimal management remains uncertain.

SMFM consult series #49 on cesarean scar pregnancy

What is cesarean scar pregnancy, and what is its incidence?

CSP occurs when an embryo implants in the fibrous scar tissue of a prior cesarean hysterotomy. Although sometimes called a “cesarean ectopic pregnancy,” these gestations are, in fact, within the uterine cavity and, unlike true ectopic pregnancies, may result in a liveborn infant. This condition presents a substantial risk for severe maternal morbidity complicated by challenges in securing timely diagnosis, as well as uncertainty regarding optimal treatment once identified.

The true incidence of CSP is unknown, as the condition is likely underdiagnosed and underreported. Reported single-center estimates of incidence range from 1:1800 to 1:2656 of overall pregnancies. Although relatively uncommon, reported international experience with CSP appears to be increasing, likely as a result of high contemporary cesarean delivery volume. Other factors, including improved imaging with ultrasound and magnetic resonance imaging (MRI), increased utilization of transvaginal ultrasonography (TVUS), and possibly increased physician awareness, may also contribute to a perceived increase in incidence.

Although the pathogenesis of CSP is incompletely understood, the mechanism has been postulated to involve blastocyst implantation within a microscopic dehiscence tract in the scar from a prior cesarean delivery. Due to the fibrous nature of scar tissue, these inherently deficient implantation sites are at risk for dehiscence, PAS, and hemorrhage as the CSP enlarges.

CSP and placenta accreta appear to have similar disease pathways and may exist along a common disease continuum. Histopathologic analyses for both groups are characterized by myometrial or scar tissue villous invasion with little or no intervening decidua.

Implantation patterns of CSP can be categorized as either endogenic (also referred to as “on the scar”) or exogenic (“in-the-niche”). Endogenic is defined as growing within the uterine cavity and exogenic as arising from a gestational sac deeply implanted into the scar that may grow toward the bladder or abdominal cavity (Figure 1).

These ultrasonographic appearances may influence obstetric prognosis. It has been suggested that early first-trimester determination of whether a CSP is growing “on the scar” or “in the niche” of the prior cesarean hysterotomy may be used to predict subsequent pregnancy outcomes. In one small, retrospective experience, patients with pregnancies growing “on the scar” had variable obstetric outcomes, whereas those with pregnancies growing “in the niche” all underwent hysterectomy with PAS at delivery.1

How does CSP present clinically, and are there known risk factors?

Although second-trimester diagnoses have been reported, CSP usually presents in the first trimester. In one review of published CSP case series, the average gestational age at diagnosis was 7.5 +/- 2.5 weeks.2 The clinical presentation is variable, ranging from asymptomatic ultrasonographic detection to a presentation with uterine rupture and hemoperitoneum, typically in the absence of a timely diagnosis. In the review mentioned above, about one-third of cases were asymptomatic, and approximately one-third presented with painless vaginal bleeding. Nearly one-quarter of presentations involved pain, with or without bleeding. Women with a ruptured CSP may also present with hemodynamic collapse. 

Although by definition prior cesarean delivery is a prerequisite for CSP development and placenta previa may modify this risk, it is not clear if the number of prior cesarean deliveries further increases risk. A review of the literature reveals that 52% of CSP cases occur in women with a single prior cesarean delivery.3-5 Previous delivery for breech presentation appears to be a more common indication in women who later develop CSP. No published data exist regarding an association between hysterotomy closure technique and CSP.

TVUS is the optimal modality for evaluation of suspected CSP, as it provides the highest image resolution (Figures 2 and 3). Grayscale combined with color Doppler ultrasound is recommended for CSP diagnosis. One group suggests combining TVUS with a transabdominal ultrasonogram with a full maternal bladder to provide a “panoramic view” of the uterus and the relationship between the gestational sac and bladder.6 The initial finding of a low, anteriorly located gestational sac should raise concern for a possible CSP and warrants further investigation. When evaluating women with suspected CSP, a high degree of clinical suspicion is needed as a missed or delayed diagnosis can result in uterine dehiscence, hemorrhage, loss of fertility, or maternal death. 

Diagnostic criteria have been proposed to enhance ultrasonographic detection of CSP.4,7,8 One approach proposes the following ultrasonographic criteria to diagnose CSP: (1) an empty uterine cavity and endocervix; (2) placenta, gestational sac, or both embedded in the hysterotomy scar; (3) a triangular ( ≤8 weeks of gestation) or rounded or oval (> 8 weeks of gestation) gestational sac that fills the scar “niche” (the shallow area representing a healed hysterotomy site); (4) a thin (1-3 mm) or absent myometrial layer between the gestational sac and bladder; (5) a prominent or rich vascular pattern at or in the area of a cesarean scar; and (6) an embryonic or fetal pole, yolk sac, or both with or without fetal cardiac activity (Figure 4). All of these criteria may not be observed. Especially with very early diagnosis and before fetal cardiac activity, the woman must have confirmation of pregnancy (for example, a positive pregnancy test result). Bulging or ballooning of the lower uterine segment in the midline sagittal transabdominal view has also been considered to be supportive of CSP diagnosis. 

Distinguishing CSP from other clinical entities with a similar ultrasonographic appearance is challenging. CSP may be misdiagnosed as either cervical ectopic pregnancy, spontaneous abortion in transit, or low implantation of an intrauterine pregnancy. Given the importance of prompt diagnosis, referral to an experienced center for a second opinion may be preferable to ongoing follow-up examinations that are likely to lead to a delay in diagnosis.

Are other modalities useful for diagnosis?

Transvaginal three-dimensional (3D) ultrasound and 3D power ultrasound have been used in an attempt to enhance accuracy of CSP diagnosis. However, data are insufficient to support a benefit of routine use of 3D ultrasound for diagnosis or management of CSP. Magnetic resonance imaging (MRI) has been used as an adjunct to ultrasound for diagnosis of CSP, although its incremental benefit over ultrasound alone is unknown. MRI may provide useful information regarding the degree of invasion and whether there is evidence of PAS. Most authors do not recommend MRI as a routine component of CSP evaluation. In cases in which ultrasound imaging is inconclusive, MRI could be considered as an adjunct study. Given the risks associated with delayed diagnosis, use of multiple ultrasound imaging approaches, as well as modalities such as MRI, are likely preferable to serial ultrasound examinations.

Hysteroscopy and laparoscopy can be used to confirm a diagnosis at the time of planned operative intervention. With laparoscopic examination, CSP has been described as an ecchymotic bulge with a “salmon-red” appearance beneath the bladder at the level of the prior cesarean scar with an otherwise normal-appearing uterus.

Although few recognized CSPs continue to a viable gestational age, some CSPs have resulted in live births often associated with PAS, cesarean hysterectomy, and massive hemorrhage at delivery. Series describing outcomes of expectantly managed CSPs all involve small case numbers and high hysterectomy rates, ranging from 50% to 100% and usually associated with PAS. In case series of women managed expectantly, most required additional treatment, and more than 50% had severe complications.9-13

Due to the high risk of severe maternal morbidity, expectant management is not recommended for a recognized CSP, and pregnancy termination is generally advised as soon as the diagnosis is confirmed. For cases in which a CSP is suspected but the diagnosis is not certain, short-interval follow-up, a second opinion, or additional imaging with MRI should be considered to make a timely diagnosis without undue delay. We recommend against expectant management of cesarean scar pregnancy (GRADE 1B).

An exception to the recommendation against expectant management involves early CSP that is definitively diagnosed as nonviable. In this situation, expectant management may be pursued with serial ultrasound surveillance, quantitative beta-hCG measurements, and monitoring for maternal symptoms such as bleeding or pelvic pain. It can take several months for a nonviable CSP to resolve spontaneously, and expectant management of nonviable CSP has been associated with development of a uterine arteriovenous malformation (AVM). Uterine AVM in this clinical context has been associated with persistent, severe vaginal bleeding and may require umbilical artery embolization or even hysterectomy.

What CSP treatment modalities have been reported?

Surgical, medical, and minimally invasive therapies, as well as various combinations of such treatments, have been described, including hysteroscopy, laparoscopy, laparotomy, open surgery, transvaginal surgery, dilation and curettage (D&C, including both sharp and vacuum aspiration techniques), uterine artery embolization (UAE), methotrexate (MTX) (both local guided injection and systemic administration), direct potassium chloride (KCl) injection, needle-guided sac decompression, high-intensity focused ultrasound (HIFU), and use of balloon catheters, and combinations of these methods (Table 1).14-16

The optimal treatment is not known. Systematic reviews have been inconsistent with regard to identification of a single optimal CSP treatment modality that best balances procedural success and risks. Data regarding optimal CSP therapy consist primarily of case series with varying levels of clinical experience, institutional capability, provider skill, and case complexity. Randomized controlled trials comparing treatment approaches are limited, as are those comparing medical and surgical approaches.

CSP treatment decisions are guided by a principal goal of preserving maternal health, followed by a secondary goal of preserving fertility when possible. Management decisions should be determined after considering pregnancy viability, gestational age, maternal health, future family planning wishes, physician skill and experience, and institutional resources. Preferred management may differ between institutions based upon resources, personnel, and clinical experience. Even with efforts to tailor treatment strategies to individual patients and clinical presentations, there remains a substantial risk of complications with any management approach.

What are the recommended treatment approaches for CSP?

Among surgical management options, transvaginal and laparoscopic CSP resection appear to have low complication rates.17-19 A potential advantage of these approaches is that the scar tissue can be excised and the surrounding myometrium reapproximated at the time of CSP removal. It is unknown if this practice decreases risk of CSP reoccurrence. 

D&C alone, without adjuvant treatments, has been associated with high complication rates, including hemorrhage and perforation, due to an inability to completely access and remove trophoblastic tissue outside of the endometrial cavity and because scar tissue contracts poorly after curettage.14 As with PAS, sharp curettage may sever deeply invading blood vessels, exposing the patient to ongoing bleeding. In addition to a high complication rate, additional treatment is reported to be required after 52% of D&C cases. It should be noted that the published literature incompletely distinguishes between sharp curettage and vacuum aspiration, which may provide different success and complication rates with CSP management.14 We suggest operative resection (with transvaginal or laparoscopic approaches when possible) or ultrasound-guided vacuum aspiration be considered for surgical management of CSP and that sharp curettage (D&C) alone be avoided (GRADE 2C).

While sharp curettage alone is not recommended as a primary CSP treatment, higher efficacy and lower complication rates have been reported with ultrasound-guided vacuum aspiration.20 Shirodkar placement as an adjunct to D&C has also been described, in which the cerclage suture is placed prior to D&C and only secured in the setting of hemorrhage to minimize bleeding.21

Gravid hysterectomy is an alternative surgical option that may be considered for definitive management of CSP. This approach may be particularly appropriate for early second-trimester CSP presentations or for women who do not desire future fertility.

When pursuing medical treatment of CSP, local or intragestational injection of MTX is a preferred approach, with or without accompanying systemic MTX. Standalone systemic MTX is not recommended due to a higher reported risk of complications.7, 22 Although a small randomized trial of systemic versus local MTX demonstrated no difference in overall cure rates23, reviews suggest a high risk of complications with intramuscular MTX alone24, 25, and local MTX appears to be a more effective approach. In a literature review by Cheung et al, of 96 cases of intragestational MTX for CSP, success was achieved in 73.9% after a single local MTX injection and increased to 88.5% after an additional local or intramuscular MTX injection.25 Intragestational injection is typically performed with a 20-gauge needle under ultrasound guidance using a transvaginal approach. Sac aspiration may be performed prior to injection to verify appropriate needle placement. Optimal dosing for local MTX injection ranges from doses of 1 mg/kg of maternal weight to 50 mg. Varying dosages of systemic MTX have been reported in management of CSP; in general, these dosages are comparable to those used for ectopic pregnancy. We suggest intragestational MTX for medical treatment of CSP, with or without other treatment modalities (GRADE 2C). We recommend that systemic MTX alone not be used to treat CSP (GRADE 1C). 

When following women with CSP who have been treated medically, the gestational mass can take weeks to months to resolve. A transient increase in beta-hCG levels and CSP mass size can be observed after MTX therapy. One study of 22 women following local conservative CSP treatment reported a mean time to resolution of 88 days (range 26-177).8 An understanding of this anticipated posttherapy course may help to minimize unnecessary additional treatments. During the posttreatment observation period, patients should be monitored for concerning symptoms such as hemorrhage or uterine AVM development. Interval ultrasonographic surveillance may be helpful to observe for CSP resolution. 

Intragestational KCl has also been described for treatment of CSP in a small number of cases. This approach may be particularly appropriate for management of CSP heterotopic pregnancies with a coexisting intrauterine pregnancy, as MTX exposure may have embryocidal or teratogenic consequences for the intrauterine cotwin. As with MTX, ultrasound-guided KCl injection can be accompanied by sac aspiration. Hysteroscopic and laparoscopic approaches for treating CSP heterotopic pregnancies have also been described.

UAE is a minimally invasive procedure that has been used in various combinations to treat CSP. It has been reported as a standalone procedure, as well as in combination with D&C, MTX, and hysteroscopy, which complicates comparisons between studies.14 UAE may be a uterine- and fertility-preserving procedure, although reported outcomes in the setting of CSP vary significantly, and its role as an adjunct to other management approaches requires further study.

Ultrasound-guided placement and inflation of balloon and Foley catheters to tamponade a CSP gestational sac complicated by bleeding or as a prophylactic measure has been reported.15, 16, 26 Limited experience shows that this technique may be well tolerated and efficacious, supporting a potential option that warrants further study. 

How should CSP be managed in women who decline treatment?

Women who decline treatment of a CSP should be counseled about risk of significant obstetric complications, including PAS, massive hemorrhage, uterine rupture, severe maternal morbidity, and potentially maternal death. Management of such cases should include a very high index of suspicion for PAS with appropriate antepartum management and delivery planning. Women should be counseled regarding signs and symptoms of preterm labor or any symptoms suggesting uterine rupture. Repeat cesarean delivery is recommended between 34 0/7 and 35 6/7 weeks of gestation. As with other medically indicated late preterm births, betamethasone administration is recommended prior to delivery. In women who choose expectant management and continuation of a CSP, we recommend repeat cesarean delivery between 34 0/7 and 35 6/7 weeks of gestation (GRADE 1C).

As with PAS, delivery should occur at Level III or Level IV facilities with appropriate expertise and resources, including the capability to manage massive hemorrhage. A multidisciplinary team approach to delivery is recommended, and the team should be prepared for the potential need for cesarean hysterectomy and massive transfusion.

Women can become pregnant after uterine-preserving management of a CSP, although there appears to be an increased risk for recurrent CSP and other severe maternal morbidities. High rates of complications and severe maternal morbidity, including PAS, recurrent CSP, gravid hysterectomy, and uterine rupture, have been reported.27-30 Women considering pregnancy after a CSP should be informed that there is a significant risk of recurrence and severe maternal morbidity. We recommend that women with a CSP be advised of the risks of another pregnancy and counseled regarding effective contraceptive methods, including long-acting reversible contraception and permanent contraception (GRADE 1C).

Although a short interval between successful conservative CSP management and subsequent pregnancy may increase risk of recurrent CSP or PAS, there is no consensus about how long to wait before attempting another pregnancy for women who desire another pregnancy after counseling regarding the risks. Some experts have recommended waiting 12 to 24 months before attempting to become pregnant again, although there is limited supporting evidence.

Given the increased risk of CSP recurrence, some advocate evaluation of the uterus and cesarean scar by saline infusion sonohysterography prior to a subsequent pregnancy. However, it is not clear whether the detection of a defect is associated with higher risks and should influence counseling regarding the advisability of another pregnancy. Interpregnancy repair or revision of a cesarean scar has been reported using a variety of surgical modalities. However, data are insufficient to support a benefit to this practice.

Should a woman with a history of a CSP become pregnant, close ultrasonographic monitoring is recommended to confirm the presence of an intrauterine pregnancy and to exclude recurrent CSP or PAS. An initial ultrasound examination is recommended on presentation to prenatal care, ideally before 8 weeks of gestation, to confirm a normal intrauterine location. Repeat cesarean delivery is recommended between 34 0/7 to 35 6/7 weeks of gestation, prior to the onset of labor. Betamethasone administration is recommended prior to anticipated late preterm delivery. The delivery team should be prepared for obstetric hemorrhage and the potential need for cesarean hysterectomy.

Due to high worldwide cesarean delivery rates, an increased incidence of CSP has been recognized. CSP can be difficult to diagnose in a timely fashion, and this diagnosis should be considered in women with a prior cesarean delivery who are undergoing early first-trimester ultrasonography. Several surgical and medical treatments have been described for this disorder, but at this time, optimal management remains uncertain. For this reason, an international registry has been created for providers to submit data on diagnosis, natural history, and management (

1. Kaelin Agten A, Cali G, Monteagudo A, Oviedo J, Ramos J, Timor-Tritsch I. The clinical outcome of cesarean scar pregnancies implanted “on the scar” versus “in the niche.” Am J Obstet Gynecol 2017;216(5):510.e1–510.e6.
2. Rotas MA, Haberman S, Levgur M. Cesarean scar ectopic pregnancies: etiology, diagnosis, and management. Obstet Gynecol 2006 Jun;107(6):1373-81.3.
3. Jurkovic D, Hillaby K, Woelfer B, Lawrence A, Salim R, Elson CJ. First-trimester diagnosis and management of pregnancies implanted into the lower uterine segment Cesarean section scar. Ultrasound Obstet Gynecol 2003 Mar;21(3):220-7.
4. McKenna DA, Poder L, Goldman M, Goldstein RB. Role of sonography in the recognition, assessment, and treatment of cesarean scar ectopic pregnancies. J Ultrasound Med 2008 May;27(5):779-83.
5. McKenna DA, Poder L, Goldman M, Goldstein RB. Role of sonography in the recognition, assessment, and treatment of cesarean scar ectopic pregnancies. J Ultrasound Med 2008 May;27(5):779-83.
6. Maymon R, Halperin R, Mendlovic S, Schneider D, Herman A. Ectopic pregnancies in a Caesarean scar: review of the medical approach to an iatrogenic complication. Hum Reprod Update 2004 Nov-Dec;10(6):515-23.
7. Vial Y, Petignat P, Hohlfeld P. Pregnancy in a cesarean scar. Ultrasound Obstet Gynecol 2000 Nov;16(6):592-3.
8. 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 Jul;207(1):44 e1-13.
9. Timor-Tritsch IE, Monteagudo A, Cali G, Palacios-Jaraquemada JM, Maymon R, Arslan AA, et al. Cesarean scar pregnancy and early placenta accreta share common histology. Ultrasound Obstet Gynecol 2014 Apr;43(4):383-95.
10. Ben Nagi J, Ofili-Yebovi D, Marsh M, Jurkovic D. First-trimester cesarean scar pregnancy evolving into placenta previa/accreta at term. J Ultrasound Med 2005 Nov;24(11):1569-73.
11. Zosmer N, Fuller J, Shaikh H, Johns J, Ross JA. Natural history of early first-trimester pregnancies implanted in Cesarean scars. Ultrasound Obstet Gynecol 2015 Sep;46(3):367-75.
12. Michaels AY, Washburn EE, Pocius KD, Benson CB, Doubilet PM, Carusi DA. Outcome of cesarean scar pregnancies diagnosed sonographically in the first trimester. J Ultrasound Med 2015 Apr;34(4):595-9.
13. Cali G, Timor-Tritsch IE, Palacios-Jaraquemada J, Monteaugudo A, Buca D, Forlani F, et al. Outcome of Cesarean scar pregnancy managed expectantly: systematic review and meta-analysis. Ultrasound Obstet Gynecol 2018 Feb;51(2):169-75.
14. 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.
15. Monteagudo A, Cali G, Rebarber A, et al. Minimally invasive treatment of cesarean scar and cervical pregnancies using a cervical ripening double balloon catheter: expanding the clinical series. J Ultrasound Med 2019;38: 785–93.
16. Timor-Tritsch IE, Monteagudo A, Bennett TA, Foley C, Ramos J, Kaelin Agten A. A new minimally invasive treatment for cesarean scar pregnancy and cervical pregnancy. Am J Obstet Gynecol 2016;215:351.e1–8.
17. Kang SY, Park BJ, Kim YW, Ro DY. Surgical management of cesarean scar ectopic pregnancy: hysterotomy by transvaginal approach. Fertil Steril 2011 Jul;96(1):e25-8.
18. Le A, Shan L, Xiao T, Zhuo R, Xiong H, Wang Z. Transvaginal surgical treatment of cesarean scar ectopic pregnancy. Arch Gynecol Obstet 2013 Apr;287(4):791-6.
19. Wang DB, Chen YH, Zhang ZF, Chen P, Liu KR, Li Y, et al. Evaluation of the transvaginal resection of low-segment cesarean scar ectopic pregnancies. Fertil Steril 2014 Feb;101(2):602-6.
20. Jurkovic D, Knez J, Appiah A, Farahani L, Mavrelos D, Ross JA. Surgical treatment of Cesarean scar ectopic pregnancy: efficacy and safety of ultrasound-guided suction curettage. Ultrasound Obstet Gynecol 2016 Apr;47(4):511-7.
21. Jurkovic D, Ben-Nagi J, Ofilli-Yebovi D, Sawyer E, Helmy S, Yazbek J. Efficacy of Shirodkar cervical suture in securing hemostasis following surgical evacuation of Cesarean scar ectopic pregnancy. Ultrasound Obstet Gynecol 2007 Jul;30(1):95-100.
22. Osborn DA, Williams TR, Craig BM. Cesarean scar pregnancy: sonographic and magnetic resonance imaging findings, complications, and treatment. J Ultrasound Med 2012 Sep;31(9):1449-56.
23. Peng P, Gui T, Liu X, Chen W, Liu Z. Comparative efficacy and safety of local and systemic methotrexate injection in cesarean scar pregnancy. Ther Clin Risk Manag 2015;11:137-42.
24. 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 Jul;207(1):14-29.
25. Cheung VY. Local methotrexate injection as the first-line treatment for cesarean scar pregnancy: review of the literature. J Minim Invasive Gynecol 2015 Jul-Aug;22(5):753-8.
26. Timor-Tritsch IE, Cali G, Monteagudo A, Khatib N, Berg RE, Forlani F, et al. Foley balloon catheter to prevent or manage bleeding during treatment for cervical and Cesarean scar pregnancy. Ultrasound Obstet Gynecol 2015 Jul;46(1):118-23.
27. Seow KM, Hwang JL, Tsai YL, Huang LW, Lin YH, Hsieh BC. Subsequent pregnancy outcome after conservative treatment of a previous cesarean scar pregnancy. Acta Obstet Gynecol Scand 2004 Dec;83(12):1167-72.
28. Sadeghi H, Rutherford T, Rackow BW, Campbell KH, Duzyj CM, Guess MK, et al. Cesarean scar ectopic pregnancy: case series and review of the literature. Am J Perinatol 2010 Feb;27(2):111-20.
29. Wang Q, Peng HL, He L, Zhao X. Reproductive outcomes after previous cesarean scar pregnancy: follow up of 189 women. Taiwan J Obstet Gynecol 2015 Oct;54(5):551-3.
30. Grechukhina O, Deshmukh U, Fan L, Kohari K, Abdel-Razeq S, Bahtiyar MO, et al. Cesarean scar pregnancy, incidence, and recurrence: five-year experience at a single tertiary care referral center. Obstet Gynecol 2018; 132(5):1285-95.

Cesarean scar pregnancy (CSP) is a complication in which an early pregnancy implants in the scar from a prior cesarean delivery. Incidence and recognition of this condition appear to have increased over the past two decades, perhaps due to high worldwide cesarean delivery rates. 

The clinical presentation is variable, and many women are asymptomatic at presentation. CSP can be difficult to diagnose in a timely fashion. Ultrasound is the primary imaging modality for CSP diagnosis.

Expectantly managed CSP is associated with high rates of severe maternal morbidity such as hemorrhage, placenta accreta spectrum (PAS), and uterine rupture. Given these substantial risks, pregnancy termination is recommended after CSP diagnosis. Several surgical and medical treatments have been described for this disorder, but at this time, optimal management remains uncertain. 

The Society for Maternal-Fetal Medicine consult series #49 on cesarean scar pregnancy

In the United States, 1% to 2.5% of pregnant women are infected with hepatitis C virus (HCV), which carries an approximately 5% risk of transmission from mother to infant. HCV can be transmitted to an infant in utero or during the peripartum period. Two primary concerns arise from HCV in pregnancy: 1) maternal well-being, i.e., the effect of pregnancy on the course of chronic HCV infection; and 2) fetal well-being, namely mother-to-infant transmission of HCV and the impact of maternal infection on pregnancy outcomes. 

What is the natural course of HCV infection?

In addition to vertical transmission, HCV is transmitted through percutaneous exposure to blood through use of contaminated needles for injection of illicit drugs or during occupational exposure. Sexual intercourse is an inefficient means of transmission. The first 6 months after exposure to HCV is referred to as acute HCV infection, which is asymptomatic in 75% of cases. When symptoms occur, they include abdominal pain, nausea, anorexia, jaundice, or malaise. Without treatment, approximately 15% of infected individuals spontaneously clear HCV within 6 months of infection, although some estimate this number to be as high as 45%. Those who do not clear the virus harbor it for the rest of their lives and develop chronic HCV infection, which accounts for most HCV-associated morbidity and mortality, mainly due to cirrhosis and hepatocellular carcinoma.

Researchers speculate that down-regulation of the maternal immune response that occurs during pregnancy may reduce the amount of immune-mediated hepatocellular damage caused by HCV. This mechanism would also account for the decrease in alanine transaminase (ALT) levels seen in pregnant women with HCV and the increase in serum levels of HCV RNA during the second and third trimesters of pregnancy. Some histological evidence also suggests that pregnancy may be associated with a decrease in HCV-mediated hepatic injury, but data are conflicting.

What is the impact of HCV on pregnancy outcomes?

HCV infection is associated with adverse pregnancy outcomes. Two population-based, retrospective cohort studies and a recent meta-analysis found that infants born to women infected with HCV were more likely to have poor birth outcomes, including fetal growth restriction, low birth weight (LBW), and congenital anomalies, and to be delivered preterm. It is difficult to know with certainty whether the increased risk of adverse outcomes such as fetal growth restriction and LBW is due to the viral effect of HCV or to potential confounders in the population being studied.

In addition, several studies have reported higher rates of gestational diabetes in HCV-infected women compared with noninfected women, although in one of these studies, this association was limited to women with excessive weight gain during pregnancy. Another population-based, retrospective cohort study found that infants born to HCV-infected women were more likely to have feeding difficulties and other adverse neonatal outcomes, including cephalohematoma, brachial plexus injury, fetal distress, intraventricular hemorrhage, or neonatal seizures.

Intrahepatic cholestasis of pregnancy (ICP) has also been associated with HCV infection. The overall incidence of ICP in the general obstetric population is 0.2% to 2.5%, while the odds of developing ICP are 20-fold higher in HCV-infected pregnant women. Given the increased risk of fetal death associated with ICP, diagnosis of this disease in pregnant women is important.

Currently, a multicenter, prospective observational cohort study is underway to evaluate pregnancy outcomes in women with HCV. Outcomes being studied include preterm delivery, gestational diabetes, preeclampsia, cholestasis, and infant birth weight (Clinicaltrials.gov: NCT01959321).

What is the rate of vertical transmission of HCV?

Vertical transmission of HCV is the leading cause of HCV infection in children. While one-third to one-half of mother-to-child transmission of HCV appears to occur in utero prior to the last month of pregnancy, the remainder is thought to occur either in the last month of pregnancy or during delivery. In women who are coinfected with HIV and HCV, risk of vertical transmission is almost double that in women infected only with HCV.

In general, vertical transmission of HCV is thought to be a risk only for women with detectable HCV RNA during pregnancy. Whether the level of HCV viremia correlates with risk of transmission has yet to be determined. Several studies have shown that higher viral loads correlate with an increased risk of transmission, whereas other studies have failed to find such an association.

Who should be screened for HCV during pregnancy and what is the ideal screening test for HCV?

Current guidelines from the American College of Obstetricians and Gynecologists (ACOG) and the Centers for Disease Control and Prevention (CDC) recommend risk-based screening for HCV in pregnant women. We recommend that obstetric care providers screen women who are at increased risk for HCV by testing for anti-HCV antibodies at their prenatal visit. If initial results are negative, HCV screening should be repeated later in pregnancy in women with persistent or new risk factors for HCV infection after their initial screening (e.g., new or ongoing use of injected or intranasal illicit drugs).

The standard screening test for HCV is an anti-HCV antibody test. Anti-HCV antibodies usually develop 2 to 6 months after exposure-during the acute phase of infection-and persist throughout life. A positive test result indicates one of the following: the patient has active HCV infection (acute or chronic), the patient had a past infection that has resolved, or the result is a false positive.

A positive anti-HCV antibody result should be followed by a quantitative nucleic acid test for HCV RNA. Diagnosis of HCV infection depends on detection of anti-HCV antibodies and HCV ribonucleic acid (RNA). HCV viremia, i.e., the presence of HCV RNA in the blood, indicates active infection and can first be detected 1 to 3 weeks after exposure.

What other additional evaluation should occur? 

For pregnant women with confirmed active HCV infection, a quantitative HCV RNA test should be done to determine baseline viral load. Basic laboratory testing to evaluate the extent of liver disease should include the following laboratory tests: bilirubin, ALT and aspartate aminotransferase (AST), albumin, platelet count, and prothrombin time. To help plan future treatment, testing for HCV genotype should also be performed (if not done previously).

In light of common risk factors, we recommend that obstetric care providers screen HCV-positive pregnant women for other sexually transmitted diseases, including HIV, syphilis, gonorrhea, chlamydia, and hepatitis B (HBV). Patients with HBV infection and a high viral load can be offered antenatal treatment; infants should receive the hepatitis B vaccine as well as hepatitis immune globulin. Hepatitis A virus (HAV) infection can also worsen hepatic damage if present with HCV infection. The Advisory Committee on Immunization Practices (ACIP) recommends that women with HCV infection who are found to be at risk of  HBV and/or HAV be vaccinated, and it is safe to do so during pregnancy.

Should HCV be treated pharmacologically during pregnancy?

Until 2011, the standard-of-care treatment for chronic HCV was pegylated interferon (PegIFN)-Î± and ribavirin. In 2011, direct-acting antiviral medications (DAAs) were released, revolutionizing treatment of HCV. These drugs directly inhibit proteins involved in HCV replication, have fewer side effects than interferon-based regimens, and have led to sustained virological response (SVR) rates as high as 60% to 100%. Treatment regimens usually involve multiple DAAs to prevent viral resistance. 

Because there are no adequate human data regarding any of the effects of second-generation DAAs in pregnancy, we recommend that DAA regimens only be used in the setting of a clinical trial or antiviral treatment should be deferred to the postpartum period as DAA regimens are not currently approved for use in pregnancy.

What are the principles of medical management of HCV during pregnancy?

Any woman who is diagnosed with HCV infection during pregnancy should be referred to a hepatologist or infectious disease specialist experienced in management of hepatitis in order to establish long-term care.

Use of even modest amounts of alcohol has been associated with progression of liver disease, and we suggest that patients with HCV, including pregnant women, be counseled to abstain from alcohol.

Serial laboratory surveillance of liver function or serial viral load assessment during pregnancy in HCV-positive women is generally not recommended. As discussed previously, serum levels of ALT tend to decrease during the second and third trimesters of pregnancy, i.e., liver function is expected to improve, not worsen, during pregnancy.

Is invasive prenatal diagnostic testing safe in pregnant women with HCV?

Amniocentesis does not appear to increase risk of vertical transmission, although this conclusion is based on limited data. No studies have been published on risk of vertical transmission of HCV with other invasive prenatal testing modalities, including chorionic villus sampling (CVS). We suggest that if invasive prenatal diagnostic testing is requested, women be counseled that data on the risk of vertical transmission are reassuring but limited; amniocentesis is recommended over CVS given lack of data on the latter.

Does mode of delivery affect risk of vertical transmission?

Mode of delivery-vaginal versus cesarean-has not been shown to be a risk factor for vertical transmission of HCV. However, because all published studies on mode of delivery and risk of vertical transmission of HCV are observational and most did not assess viral load at the time of delivery, these results should be interpreted cautiously. We recommend against cesarean delivery solely for the indication of HCV.

Does labor management affect risk of vertical transmission? 

Several factors in labor management may be associated with increased risk of vertical transmission of HCV, namely prolonged rupture of membranes, internal fetal monitoring, and episiotomy. Based on the available evidence, we recommend that obstetric care providers avoid internal fetal monitoring, prolonged rupture of membranes, and episiotomy in managing labor in HCV-positive women, unless it is unavoidable in the course of management. We also recommend that obstetric care providers avoid early amniotomy and episiotomy in managing labor in HCV-positive women.

Is breastfeeding safe for HCV-positive mothers?

Breastfeeding does not appear to affect the risk of vertical transmission of HCV. We recommend against discouraging breastfeeding based on a positive HCV infection status. If women have cracked and bleeding nipples, milk should be expressed and discarded.

How should infants born to HCV-positive women be screened for HCV infection?

Because anti-HCV antibodies can be transmitted across the placenta from a pregnant woman to the fetus, the presence of anti-HCV antibodies in a neonate’s serum soon after delivery is not diagnostic of neonatal infection. The American Academy of Pediatrics and CDC recommend screening of infants born to HCV-positive women for anti-HCV antibodies after age 18 months or for HCV RNA on two occasions in infants older than age 1 month.

In the United States, 1% to 2.5% of pregnant women are infected with hepatitis C virus (HCV), which carries an approximately 5% risk of transmission from mother to infant. HCV can be transmitted to an infant in utero or during the peripartum period.

Author | Society for Maternal-Fetal Medicine (SMFM)

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