Learning Objectives:After participating in this continuing professional development activity, the provider should be better able to:

1. Define cervical ectopic and cesarean scar pregnancy and associated risk factors.

2. Interpret ultrasound imaging findings and propose medical and surgical management strategies for patients with pregnancy implanted in the cervix or cesarean scar.

3. Summarize patient counseling on potential morbidity, future fertility, and risk of recurrence after management of a cervical or cesarean scar pregnancy.

A 30-year-old gravida 3 para 2002 woman at 5 weeks estimated gestational age by her last menstrual period presents to the emergency department with mild cramping and vaginal bleeding. Examination demonstrates a small amount of dark red bleeding and mild, diffuse tenderness to palpation over bilateral lower abdominal quadrants. Her vital signs are normal. Laboratory workup is unremarkable, consistent with pregnancy with a beta-human chorionic gonadotropin ([beta]hCG) value of 3700 IU/L. She is Rh positive. Ultrasound shows a yolk sac consistent with gestational age in the lower portion of the uterus, near the cervix (Figure 1). Most obstetrician-gynecologists have cared for many patients with this scenario, and usually the diagnosis is simple: an early intrauterine pregnancy of uncertain viability. It is critical, however, to recognize that a small percentage of these cases can represent abnormal, potentially dangerous, and even life-threatening pregnancies requiring further evaluation and management.

Figure 1. Case example: early lower uterine segment pregnancy.

Ectopic pregnancy is defined as the implantation of an embryo outside of the endometrium. It is common in healthy women with an overall prevalence of 1% to 2%. Rates are increased in patients using assisted reproductive technology, estimated at approximately 2% to 5%.1-3 The incidence of ectopic pregnancy has increased over time, likely secondary to both increasing associated risk factors and improved recognition. The most common location of an ectopic pregnancy is in the fallopian tube, though implantation can also occur in other structures, such as the ovary, abdomen, or cervix. Fewer than 10% of all ectopic pregnancies occur outside the fallopian tube, but these ectopic pregnancies contribute more significantly to maternal morbidity and mortality compared with tubal ectopic pregnancies.4

Cervical ectopic pregnancies are defined by their implantation within the cervical canal. They account for fewer than 1% of all ectopic pregnancies with a reported incidence of anywhere from 1 in 2000 to 1 in 18,000.4,5 Pregnancies can also implant abnormally into a previous cesarean delivery scar. Some experts do not consider this an ectopic pregnancy, as the pregnancy can grow into the uterine cavity, though these pregnancies are dangerous and abnormal. Estimates of the incidence of cesarean scar pregnancy range from 1 in 1700 to 1 in 3000 pregnancies,6,7 and this rate has increased over time concordantly with the rate of cesarean deliveries. Seow et al8 estimate 0.15% of all women with previous cesarean delivery will develop a cesarean scar ectopic. Another study estimated that cesarean scar pregnancies account for 6.1% of ectopic pregnancies in women with a history of at least 1 previous cesarean delivery.9 The rarity of cervical and cesarean scar pregnancies means the majority of evidence originates from case reports and observational studies. High-quality evidence to guide clinical practice remains scarce.

Although the above case certainly could represent an early normal uterine pregnancy or a spontaneous abortion in progress, cervical ectopic and cesarean scar pregnancies are important differential considerations. The goal of this article is to review the evaluation and diagnosis of such a patient, with an emphasis on the recognition and management of cervical and cesarean scar pregnancies.

Pathogenesis and Risk Factors

The majority of observational studies suggest a relationship between cervical and cesarean scar pregnancies and damage incited by previous procedures. Many additional risk factors are similar to those for other types of ectopic pregnancy and are summarized in Table 1.

Table 1. Risk Factors

Cervical Ectopic Pregnancy

Some procedures have the potential to damage the endocervix and cause decidual proliferation of the endocervical epithelium. History of dilation and curettage is associated with almost 70% of cases of cervical ectopic pregnancy.10 Previous dilation and curettage is also frequently associated with the use of assisted reproductive technology to conceive, a second risk factor. Other suggested risk factors include Asherman's syndrome, presence of intrauterine device (IUD), leiomyoma, and previous cesarean delivery.

Cesarean Scar Pregnancy

The suggested pathogenesis of cesarean scar pregnancy includes a small tract or dehiscence within the previous cesarean scar allowing the pregnancy to invade into the scar and implant.6,11 There are 2 suggested phenotypes of cesarean scar pregnancies: type I or "endogenic" involves growth toward the uterine cavity, and type II or "exogenic" involves those that invade deep into the scar and grow outward toward the bladder and abdominal cavity.7,12 Only endogenic-type cesarean scar pregnancies have the potential to result in viable pregnancy, though not without significant risk. Some experts have also associated cesarean scar pregnancy with placenta accreta spectrum, and think these conditions may exist along a common disease pathway.6,13

Previous cesarean delivery is a defining characteristic. According to Centers for Disease Control and Prevention data, the US cesarean delivery rate increased annually from 21% in 1996 to its peak of 32.9% in 2009. It has remained between 31% and 32% since, with more than 1.1 million cesarean deliveries per year in the United States.14 Studies on whether the number of previous cesarean deliveries increases risk have shown mixed results. One observational study of 112 patients with cesarean scar pregnancy demonstrated 52% of patients had only one previous cesarean delivery. Additional analysis found the rate to be 36% after 2 previous cesarean deliveries, and 12% after 3 or more previous cesarean deliveries.7 Jurkovic et al9 interestingly found contradictory results in their 2003 study, with 72% of all cases having had multiple previous cesarean deliveries. They proposed that multiple previous cesarean deliveries are a strong risk factor given possible increased scar surface area.9 Other risk factors cited to predispose patients to cesarean scar pregnancy include previous myomectomy, adenomyosis, use of assisted reproductive technology, previous dilation and curettage, and previous manual extraction of the placenta.2,4,15 Some remaining, less studied questions include whether the type of hysterotomy closure affects risk, and indication for cesarean delivery. Authors have proposed possible thinning of the lower uterine segment (either from vertex presentation and/or a laboring uterus) decreases the thick, fibrous nature of the scar tissue in comparison to a nonvertex presentation and/or an elective, scheduled cesarean delivery. It has been hypothesized that a thicker scar may lead to an increased risk of poor healing with resultant microscopic areas of separation and potentially increased risk for abnormal implantation.4,6,16

Clinical Features and Associated Morbidity

Initial clinical presentation can vary, from completely asymptomatic to vaginal bleeding and abdominal pain, to hemodynamic instability in the setting of pregnancy rupture. There is considerable overlap in clinical features with threatened and spontaneous abortion. A high degree of clinical suspicion and appropriate diagnostic tools are key to recognition.

Cervical Ectopic Pregnancy

The majority of cervical ectopic pregnancies present in the first trimester, with a mean age of 7 to 8 weeks. The most commonly cited presenting feature is vaginal bleeding, seen in 79% to 91% of patients.17-19 The patient may also report cramping and lower abdominal pain. An observational study by Murji et al18 in 2015 demonstrated approximately 10% of patients were completely asymptomatic at the time of diagnosis, and conversely 11% presented with acute life-threatening hemorrhage. Due to close proximity to the uterine vessels, growth and subsequent rupture of cervical ectopic pregnancy can cause severe bleeding, hemodynamic collapse, and even death.

Cesarean Scar Pregnancy

Clinical presentation of cesarean scar pregnancy is similar. Reported mean gestational age of diagnosis is usually in the first trimester with a reported range of 6.7 to 7.5 weeks.7,15 The most commonly cited symptom is again vaginal bleeding, with one reported observational study showing a rate of 86.4%.15 Other presenting symptoms included abdominal pain, hemodynamic collapse due to acute rupture, and asymptomatic clinical presentation with diagnosis on routine ultrasound.7,15 Just as with cervical ectopic pregnancies, cesarean scar pregnancies can result in severe morbidity if allowed to continue without treatment. Particularly at more advanced gestational ages, there is risk of uterine rupture, severe acute hemorrhage, and death. In those rare pregnancies that progress to live births, the majority of cases are associated with placenta accreta requiring hysterectomy with reported rates of 50% to 100%.6,7,13,20

Diagnosis

Finding the correct diagnosis requires a thorough history and physical examination, keeping in mind the previously mentioned risk factors and presenting symptoms. Laboratory studies to consider include a complete blood count (CBC), type and screen, and quantitative [beta]hCG. The best imaging study cited to diagnose both cervical and cesarean scar pregnancies is transvaginal ultrasound, including the use of color Doppler flow. Additional imaging studies to consider in cases of uncertainty include MRI and 3D ultrasound technology, though these studies should not be routinely performed due to minimal supporting evidence of their utility. Literature frequently acknowledges the difficulty of accurate ultrasound diagnosis. This is particularly true at early gestational ages, where uterine landmarks may not be as well demarcated as in the above case example. One review by Rotas et al7 demonstrated that out of 111 cesarean scar pregnancies, 94 (84.6%) were diagnosed correctly by transvaginal ultrasound, with the remaining 17 (15.4%) diagnosed incorrectly as incomplete abortions or cervical pregnancies. In another review, Jurkovic et al9 similarly found 107 of 751 (14%) cases of cesarean scar pregnancy were misdiagnosed. Having a dedicated unit for early obstetric care has been cited to improve diagnostic recognition of nontubal ectopic pregnancies.2

Cervical Ectopic Pregnancy

Values of [beta]hCG at the time of diagnosis of cervical pregnancy have been reported to be in an extremely broad range, from 610 to 163,700 IU/L.17,18 The initial value by itself is of little utility, but the trend in [beta]hCG over serial measurements is critical in making the correct diagnosis in uncertain cases, to understand the expected success versus failure of certain treatments, and to follow cases to resolution after treatment. Imaging diagnostic findings of cervical pregnancy have been proposed by multiple authors and are summarized in Table 2.2,4

Table 2. Diagnostic Criteria on Transvaginal Ultrasound and Example Images

Cesarean Scar Pregnancy

Reported values of [beta]hCG at the time of diagnosis of cesarean scar pregnancy similarly have a wide range, from less than 5000 to more than 100,000 IU/L in various reviews.6,7 Ultrasound diagnostic criteria and delineation of the 2 aforementioned cesarean scar phenotypes were first proposed by Vial et al in 2000.21 Ultrasound criteria have since been elaborated on by additional authors. Timor-Tritsch et al outlined a clear set of features seen on transvaginal ultrasound that along with a positive pregnancy test can assist with diagnosis; these criteria are listed in Table 2. Additionally, bulging or ballooning of the lower uterine segment can frequently be seen when viewing the lower uterine segment in the midline sagittal transabdominal view.6

Management

Numerous treatment methods have been reported for cervical and cesarean scar pregnancy. There is limited clear evidence to guide management due to the rarity of these conditions and because treatments are often performed in combination in cited reports. A 2020 Cochrane review attempting to compare interventions for nontubal ectopic pregnancy was only able to find randomized controlled trials for one type of nontubal ectopic pregnancy: cesarean scar pregnancy. Quality of evidence found ranged from moderate to very low.22 For the sake of simplicity, this article focuses on individual treatments as primary individual therapies. There are multiple studies that examine these therapies in combination, without clear evidence of superior efficacy.

Management can be categorized into 3 classes: expectant, medical, and surgical (summarized in Figure 2). Typical goals in management to consider include efficacy, risk of complications, and preservation of fertility. It is key to consider resources available, institutional protocols, and specialist involvement. Despite the below-outlined evidence, the best management strategy at one individual hospital may differ from another depending on provider expertise, training, and resource availability. Potential specialists to consult include minimally invasive gynecologic surgery, reproductive endocrinology and infertility, maternal fetal medicine, and family planning. It is important to also remember basic tenets of early abnormal pregnancy care; for example, the administration of RhoGAM in the case of Rh negativity.

Figure 2. Basic algorithm for management of cervical and cesarean scar pregnancies.

In the case of diagnostic uncertainty (particularly with early gestational age), one can consider short-interval follow-up with serial [beta]hCG measurements and interval imaging. Consultation of a specialist and/or second opinion may also be warranted to aid in diagnosis, remembering that later gestational ages are often more difficult and riskier to treat.

Expectant Management

Expectant management is not recommended in either confirmed cervical or cesarean scar pregnancy due to the aforementioned danger of rupture, severe hemorrhage, danger to surrounding organs, hemodynamic collapse, and even death. The only situation in which a pregnancy could potentially survive to viability is the case of an endogenic cesarean scar pregnancy, given it grows toward/into the uterine cavity. The risks associated with this scenario are still high enough that the majority of experts including the Society of Maternal Fetal Medicine strongly recommend termination of pregnancy upon diagnosis.6 In case reports of expectant management for cesarean scar pregnancy, complications are exceedingly high. Rotas et al7 observed that 3 of 6 of patients managed expectantly experienced uterine rupture, severe hemorrhage, and disseminated intravascular coagulation mandating hysterectomy. The remaining cases also had severe bleeding treated with salvage treatments. An additional study of 11 women who elected to continue cesarean scar pregnancies expectantly similarly showed marked morbidity. Four patients delivered live offspring via cesarean delivery, 3 of whom had hysterectomies for placenta percreta. Five had second trimester complications that all led to hysterectomy.23

In the case that a patient declines treatment, they should be thoroughly counseled about the high risk of morbidity and warning signs of serious complications. In the case of an endogenic cesarean scar pregnancy, women should be specifically educated about signs of preterm labor and uterine rupture. Repeat cesarean delivery is recommended between 34 weeks 0 day and 35 weeks 6 days of estimated gestational age. In preparation for the potential severe maternal morbidity, these deliveries should be performed at a level III or IV facility with capabilities to perform cesarean hysterectomy and with the protocol for massive transfusion.6

One may consider expectant management of a nonviable cervical or cesarean scar pregnancy, though it can take multiple months for these pregnancies to spontaneously resolve, and there is an association with the development of uterine arteriovenous malformation specifically in the case of cesarean scar pregnancy.23,24

Medical Management

Methotrexate

Methotrexate is a folate antagonist commonly used for treatment of ectopic pregnancy, and can be used for both cervical and cesarean scar pregnancies. Systemic methotrexate can be administered intramuscularly in a single-dose or multidose protocol (Table 3). Cervical and cesarean scar pregnancies can both additionally be treated with ultrasound-guided intrasac injection of methotrexate. Similar to treatment of tubal ectopic pregnancy, methotrexate is more effective in treating cervical and cesarean scar pregnancies at lower [beta]hCG levels, earlier gestational ages, and with no evidence of embryonic cardiac activity.5,23,25 Absolute contraindications to methotrexate therapy include immunodeficiency, significant cytopenia, allergy, active pulmonary or peptic ulcer disease, clinically important hepatic or renal dysfunction, breastfeeding, evidence of pregnancy rupture or hemodynamic instability, and inability to participate in follow-up. Before administration, it is important to check a CBC with differential, a [beta]hCG level, liver function tests, creatinine, and a type and screen. Benefits of medical therapy include avoiding an invasive procedure and fertility preservation. Risks include slower time to resolution, persistent teratogenicity for multiple months after treatment, persisting risk of uterine rupture and hemorrhage, and potential treatment failure requiring surgery. In general, intrasac local injection is thought to have shorter treatment time and decreased adverse effects or toxicity compared with systemic absorption, although it also requires clinician expertise.3

Table 3. Proposed Methotrexate Regimens

Additional Agents

Other therapeutics used in small case reports include gefitinib (an oral epidermal growth factor receptor inhibitor), which when given in combination with methotrexate improved the efficacy of treatment and the time to resolution of ectopic pregnancy.26 Other chemotherapeutics have also been used previously, including etoposide and actinomycin D, though there are no data on the use of these agents specifically for cervical and cesarean scar pregnancies.

Cervical Ectopic Pregnancy

Reported success rates for local or systemic therapies range between 60% and 100%. A retrospective study by Kung and Chang27 of 62 cases of cervical pregnancy cited a 91% success rate for preservation of the uterus and resolution of pregnancy with methotrexate therapy. In this study, 55% of the patients received systemic methotrexate alone, 10% received a combination of systemic and local injection therapy, and 19% received local injection alone. Intrasac potassium chloride injection was also used for 26% of cases with fetal cardiac activity.27 Jeng et al10 specifically studied intrasac aspiration followed by injection of methotrexate and potassium chloride in 38 patients with cervical ectopic; 87% of patients were successfully treated. The other 13% of patients required an additional treatment modality, with 2 receiving systemic methotrexate, and an additional 3 who received an intracervical Foley balloon to tamponade significant bleeding and a dose of systemic methotrexate.10

Cesarean Scar Pregnancy

Similar to cervical ectopic pregnancy, both systemic and local use of methotrexate has been investigated for cesarean scar pregnancy. In a 2016 systematic review of 2037 cesarean scar pregnancies by Birch Petersen et al,25 systemic methotrexate was associated with a 75% efficacy rate with a 13% complication rate. Another review of the many treatment modalities in 751 cesarean scar pregnancies by Timor-Tritsch et al23 demonstrated a considerably higher complication rate of 62.1% with systemic methotrexate alone, leading them to recommend against this treatment modality. They argued that in the case of treatment failure with this methodology, the more advanced gestational age of the pregnancy at the time of secondary treatment would result in significantly more morbidity.23 Local injection of methotrexate was associated with an efficacy of 84.5% and a complication rate of 21% in the Birch Petersen et al review, whereas in the Timor-Tritsch review it was found to have a 9.6% complication rate. A small randomized controlled trial of 104 patients comparing systemic versus local methotrexate demonstrated similar overall cure rates between the methods. Interestingly, systemic therapy was demonstrated to have a shorter time for serum [beta]hCG resolution and uterine mass disappearance.28 These authors did not compare complication rates between systemic and local therapy, though did note complications observed were mild, well tolerated, and resolved with symptomatic treatment.

Surgical Management

In a hemodynamically unstable patient, when medical therapy fails or is contraindicated, or based on patient preference, surgical management can be a highly effective way to treat cervical ectopic and cesarean scar pregnancies. Many authors argue for the use of surgical methods in the case of more advanced gestational age and higher [beta]hCG, as these pregnancies are more likely to fail medical therapy.29 Many methodologies still allow for fertility preservation, though some are significantly more invasive. Hysterectomy remains the definitive therapy for both cervical and cesarean scar pregnancies. A range of surgical methodologies have been documented to treat cervical and cesarean scar pregnancies with significant overlap. Some studies include both cervical and cesarean scar pregnancies to increase sample size. More recent studies have emphasized minimally invasive therapies over more invasive methods such as laparotomy.

In choosing the optimal therapy, it is important to consider patient wishes, particularly regarding desire for future fertility and the follow-up monitoring required. Accessibility of technology and skilled providers will dictate available methods to offer. For example, skills such as hysteroscopy and cervical balloon compression will be more widely available (in terms of both technology and provider skill) compared with transabdominal cerclage, high-intensity focused ultrasound ablation, or novel resection procedures.

Cervical Ectopic Pregnancy

The greatest challenge with the surgical management of cervical pregnancy is the proximity of these pregnancies to the rich vascular supply of the uterus and cervix. Many aspects of surgical management focus on the control of hemorrhage before attempts to remove the pregnancy. Proposed treatments to control hemorrhage and decrease vascular supply in treatment include the placement of ligating sutures, injection of vasopressin, uterine artery embolization (UAE), and balloon catheter placement. Procedures to remove the pregnancy cited include dilation and curettage, hysteroscopic resection, vaginal or laparoscopic resection, and hysterectomy.

The largest systematic review examining surgical treatment of cervical pregnancy in 454 patients reported a hysterectomy rate of 9%, with 1 patient death. More than half of the patients who underwent hysterectomy required emergent exploratory laparotomy due to heavy, uncontrolled bleeding at the time of presentation. UAE was associated with an 87.5% success rate. Dilation and curettage was associated with a 75.3% success rate. The largest complication rate associated with treatments was hemorrhage requiring transfusion, which was indicated in 2% of patients undergoing UAE and 29.4% of those undergoing dilation and curettage.5 It is important to explore the patient's desire for future fertility when considering UAE, given the theoretical concern for subsequent ischemia resulting in endometrial and/or ovarian damage. Both the American College of Obstetricians and Gynecologists and the Society of Interventional Radiology identify future fertility as a relative contraindication to this procedure. That said, successful pregnancies have been documented after UAE, with a subsequent pregnancy rate as high as 44%.5,30

Other case reports have described the other aforementioned surgical treatments. Hysteroscopic resection has shown promising results in small case series. Maglic et al31 described 3 patients who underwent small-caliber (3.8 mm) hysteroscopy for management of cervical pregnancy, with all 3 patients successfully treated and discharged home on postoperative day 1. In comparison to 7 other cases of cervical ectopic at their institution treated with dilation and curettage, the patients undergoing hysteroscopy had significantly lower blood loss and shorter hospital stay.31 Tanos et al32 similarly described use of hysteroscopic resection alone in early cervical pregnancies in 4 patients. All 4 patients were successfully treated without significant bleeding and short hospital stay (discharge 24 hours after surgery).32 Mangino et al33 described a 2-step hysteroscopic technique to treat cervical pregnancy, with step 1 focused on locating and interrupting the pregnancy via a 5-mm hysteroscope, and step 2 using a 10-mm resectoscope to remove chorionic tissue and achieve implantation site hemostasis in a single patient case study.

Placement of a cerclage has been described both as a primary method of treatment via compression and a combination method with other therapies to achieve hemostasis. Mashiach et al34 described 4 patients who underwent placement of a Shirodkar cerclage, 2 of which had previously received methotrexate unsuccessfully. Cerclage placement was successful in all cases.34 Serrati et al35 also described a more invasive though successful procedure of laparotomy with transabdominal cerclage placement in a case study of 3 patients with cervical pregnancy.

Balloon tamponade is a more recent addition to treatment options for cervical ectopic pregnancy. Multiple case reports have studied this with both single- and double-balloon catheters inserted into the cervix and inflated to compress the pregnancy and aid in hemostasis. These studies were often performed with concomitant methotrexate administration or dilation and curettage.36-38 Timor-Tritsch et al39 described the primary use of double-balloon catheter compression alone in management of both cervical and cesarean scar live pregnancies (3 and 7 cases, respectively). Treatment was successful in all cases with minimal bleeding noted and a median time of treatment to total drop of [beta]hCG of 49 days.39

Two novel technologies currently under examination for treatment are transvaginal-guided laser ablation and high-intensity focused ultrasound ablation. Both have shown promise in small case studies in patients desiring conservative therapy.40,41 More data and widespread availability of these technologies are recommended before routine implementation.

Cesarean Scar Pregnancy

Treatments for cesarean scar pregnancy differ in comparison to cervical pregnancy, given differences in blood supply (location in fibrous scar tissue) and accessibility by various routes (endogenic vs exogenic). Options explored include cervical balloon placement, UAE, repeated high-intensity focused ultrasound ablation, dilation and curettage, hysteroscopic resection, transvaginal resection, abdominal resection via laparoscopy or laparotomy, and hysterectomy. The majority of the primary literature is based on case reports, often without specification of the type of cesarean scar pregnancy (endogenic vs exogenic). Theoretically, it makes sense to distinguish between these 2 categories, as endogenic pregnancies are likely better addressed with intrauterine surgical methods such as hysteroscopy, versus exogenic pregnancies, which may be more accessible abdominally, laparoscopically, or vaginally.

The 2 large aforementioned systematic reviews of management of cesarean scar pregnancies explore the efficacy and complication rates of many of the above-listed surgical approaches, often in combination with medical management or UAE. Although these studies have significant overlap in included data, overall, a few themes emerge. UAE generally tended to increase the efficacy and decrease adverse effects of the other surgical methods when used in combination, though Timor-Tritsch and Monteagudo29 advised against UAE alone due to high risk of complications (46.9%). Dilation and curettage is not recommended as stand-alone therapy by either review, given lower efficacy (52%) and higher risk of complications and hemorrhage due to disruption of abnormal vasculature (21%-61.9%).25,29 When combining UAE with dilation and curettage however, treatment was 93.6% effective with only a 3.4% complication rate.25 Both studies proposed hysteroscopy as a widely available and highly efficacious method with a low complication rate compared with other modalities (3.2%-18.4%).25,29 Transvaginal and laparoscopic resections were noted to be generally very effective (97%-99%) and had low complication rates 0%-30.6%) but require a higher level of surgical skill and are slightly more invasive.25,29 Generally laparotomy was noted to be reserved for acutely unstable patients, given its more invasive nature and potential associated morbidity.25,29

Because the above systematic reviews have been published, multiple case reports examining the use of balloon catheters for treatment have emerged, as described above in the management of cervical ectopic pregnancy. The above-mentioned study by Timor-Tritsch et al39 in 2016 examining use of a double-balloon catheter was also successful in treating 7 live cesarean scar ectopic pregnancies. Treatment was successful in all cases with minimal bleeding noted.39 A follow-up study was published in 2018 by Monteagudo et al,42 who examined use of the method in 37 patients with cesarean scar pregnancy across 7 medical centers. Most of the patients (33 of 37) also received systemic methotrexate with the thought that this would speed time to resolution (4 patients declined this treatment). One patient had significant bleeding requiring hysterectomy 27 days after the procedure, resulting in a complication rate of 2.1%. Benefits of this therapy cited included its safety, fertility preservation, outpatient nature, and widespread availability.42

The Society for Maternal Fetal Medicine's consult series on cesarean scar pregnancy recommends transvaginal or laparoscopic resection when considering surgical management for cesarean scar pregnancy. In addition to the low complication rates noted above, the authors cite an additional potential advantage of these techniques in that they provide the opportunity to excise remaining scar tissue and reapproximate surrounding myometrium. That said, there is no evidence yet that this practice decreases risk of cesarean scar pregnancy recurrence.6

As with the management of cervical ectopic pregnancy, there are exciting data on the use of novel technologies such as high-intensity focused ultrasound ablation.43 That said, more evidence and widespread availability of this technology is required before recommendation of this approach.

Future Childbearing and Risk of Recurrence

Thinking ahead, it is important to understand the potential risk of recurrence and impact on future childbearing. Historically, the majority of these pregnancies were treated with hysterectomy, preventing future prospects for childbearing. With recent advances and a transition toward conservative therapy, less is conclusively understood regarding both rates of subsequent pregnancy, risk of recurrence, and other associated morbidity.

Cervical Ectopic Pregnancy

There are currently no studies explicitly examining the rates and risks of subsequent pregnancy after conservative treatment of a cervical ectopic pregnancy, though successful subsequent pregnancies have been documented. In the aforementioned review of management of 454 cervical pregnancies by Fowler et al,5 there were 33 cases of future pregnancy recorded. These data are somewhat difficult to interpret, given that 344 of the cases included in the study did not comment on future pregnancy.5 There are 3 published case reports of recurrence of cervical pregnancy after conservative therapy.17,44,45 More information is needed to make clear recommendations, though considering general risk factors for ectopic pregnancies, these patients are theoretically at increased risk of recurrence compared with the general population. When pregnancy is achieved, it is prudent to monitor closely. In those patients who do not desire future fertility, the full range of contraceptive options should be offered.

Cesarean Scar Pregnancy

Studies suggest a significantly increased risk of recurrence after cesarean scar pregnancy with notable associated maternal morbidity. A systematic review and meta-analysis by Morlando et al46 of 44 studies included 3598 women with cesarean scar pregnancy. The overall rate of recurrence was 17.6%. When stratified by treatment of previous cesarean scar pregnancy, 21% recurred after surgical management and 15.2% recurred after nonsurgical management. Other adverse outcomes included miscarriage (19.1%), preterm birth (10.3%), and placenta accreta spectrum disorders (4.0%); 67% of future pregnancies were uncomplicated.46 Another systematic review and meta-analysis by Wu et al47 of 32 studies and 3380 cases of cesarean scar pregnancy demonstrated a recurrence risk of 15.3%. They also noted 14.6% of subsequent intrauterine pregnancies resulted in miscarriage.47 A smaller review by Timor-Tritsch et al48 found 105 women of 252 cases examined that conceived again after treatment of cesarean scar pregnancy. The rate of cesarean scar pregnancy recurrence was 34.3%, with 27 women having a single recurrence, 3 women having multiple recurrences'1 with 2 and 1 with 4 recurrences. There were no significant differences in rates between the type of treatment of previous cesarean scar pregnancy and risk of recurrence.48 Thus, women who are considering attempting to conceive after cesarean scar pregnancy should be advised of the significant risk of recurrence, estimated to range from 15% to 30%, along with potential associated morbidity. In women who do not desire future pregnancy, contraceptive methods should be offered.

Conclusion

Cervical and cesarean scar pregnancies are rare forms of abnormal pregnancy with high rates of potential morbidity and mortality if unrecognized. Their incidence has generally increased over time. A high index of suspicion and appropriate diagnostic tools are key, as these pregnancies can easily be mistaken for spontaneous abortion in progress or early intrauterine pregnancy. The above case is a real example of an early cesarean scar pregnancy. Treatment modalities include expectant management (not recommended due to risks of massive hemorrhage, uterine rupture, and death), medical management with methotrexate, and surgical management through a variety of approaches. Often multiple treatment modalities are combined. Management requires considering patient presentation and preference, desire for future fertility, and specialist and resource availability. After successful management, counseling is warranted regarding future pregnancies and risk of recurrence. Further high-quality evidence is needed to characterize and guide management of these conditions.

Practice Pearls

* Cervical and cesarean scar pregnancies are rare and can be easily confused with an early intrauterine pregnancy or spontaneous abortion in progress.

* These pregnancies are associated with increased rates of morbidity and mortality compared with other types of ectopic pregnancy.

* Transvaginal ultrasound is the gold standard imaging modality in diagnosis.

* Expectant management is not recommended in the case of cervical or cesarean scar pregnancy, and can only rarely result in a live birth in the case of an endogenic cesarean scar pregnancy.

* Considerations for management should include efficacy of treatment, risk of complications, patient characteristics and preferences, desire for future fertility, and subspecialist and clinical resource availability.

* Medical and minimally invasive treatment modalities are generally preferred, with laparotomy reserved for hemodynamically unstable patients.

* Hysterectomy is the definitive treatment of cervical and cesarean scar pregnancies.

* Studies suggest future fertility after treatment is possible, though there is a notable risk of recurrence. This is better established for cesarean scar pregnancies.

References