Expert reviewObstetricsUnforeseen consequences of the increasing rate of cesarean deliveries: early placenta accreta and cesarean scar pregnancy. A review
Section snippets
Unexpected consequences of a cesarean delivery
The classical long-term effects of a CD such as uterine rupture, placenta previa, pathologically adherent placenta in a subsequent pregnancy, ectopic pregnancy, infertility, and intraabdominal adhesions among others were duly described in the literature and in many textbooks.
Pathologically adherent placenta at the site of a cesarean section scar in a subsequent pregnancy
The incidence of pathologically adherent placentae (accreta-increta and percreta) increases with the increasing number of CDs.16, 17, 18
Placenta accreta (PA) (we will use this term to refer to all 3 forms of pathologically adherent placentae [eg, such as accreta, increta and percreta]) was rare between 1930 and 1950, with a frequency of 1 in 30,000 deliveries. However, this frequency rose to 1/19,000 between 1950 and 1960. By 1980, the rate increased to 1/7,000. A 4-fold increase in frequency
Cesarean section scar pregnancy
Another less well-known and less studied consequence of CD is the cesarean section scar pregnancy (CSP), which, by definition, is not a classical ectopic pregnancy. The term CSP, scar pregnancy, or even the sporadically used term, isthmic pregnancy, refers to a gestational sac that has implanted in the scar or the niche of a previous cesarean delivery (Figure 1).
This serious consequence of the increasing rate of cesarean deliveries has consistently appeared in the literature in the last 10
Methodology of the review
To be able to draw practical clinical conclusions regarding the early placenta accreta (EPA) and CSP, an in-depth literature search was performed. We searched PubMed/Medline electronic databases for key words such as “pathologically adherent placenta,” “placenta accreta,” “placenta increta,” “placenta percreta,” “spontaneous uterine rupture,” “first trimester,” “second trimester,” “cesarean scar pregnancy,” “cesarean scar,” “cesarean scar ectopic,” “previous cesarean section scar,”
Results of the literature review on early placenta accreta
Forty-two articles containing descriptions of 47 cases of PA detected and treated in the first and second trimesters were found. We included 2 cases at 27 and 28 weeks because their clinical courses and outcomes were identical to those in the first trimester. Table 1 contains detailed information about their history, previous CDs' gestational age at presentation, clinical presentation, treatment, and outcome. Nine patients did not have a history of CD (19%), 31 patients had 1 CD (66%), 6
Results of the literature search on CSP
One question is whether the diagnostic entity of CSP is indeed new. Between 1990 and 1999, we found only 19 articles regarding the subject. Between 2000 and 2005, 48 articles were found, and 104 articles were published from 2006 to 2011 (Figure 1). This increase in publications is testament to the mounting awareness and attention now focused on the diagnostic challenges of this new disease.
We identified 751 CSP cases with sufficient clinical information to be evaluated for this review. We will
The diagnosis of CSP
Our own experience with scanning 26 cases with CSP made us aware of the difficulty in the diagnosis.48 Indeed, in at least 107 of the 751 cases35, 44, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81 (13.6%), the diagnosis of CSP was missed. Reading carefully the entire text of case presentation in all reviewed articles, there were at least as many cases, if not more, in which the authors did not clearly report
Findings of arterio venous malformations (A-VM)
There were 8 cases with descriptions of A-VM detected in the placentae in the scar. Some of these were diagnosed prior to interventions; others were detected as a result of treatment (current study).47, 52, 55, 82, 83 The primary management of 3 of these was by uterine artery embolization52, 82; the other 5 were managed with hysterectomies. In our own series of 26 CSPs, we had 2 cases with A-VM.48 The first of these 2 cases presented as a possible complication of a D&C procedure, whereas the
Heterotopic locations, twin/triplet, and recurrent CSP
Heterotopic pregnancies involving a CSP with singleton or twin intrauterine gestations were reported in 11 articles.84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94 The management of these cases will be discussed in the following text. Four twin cesarean section scar pregnancies were reported in 3 articles53, 83, 95: 1 single case of triplet CSP was reported.88 Six cases with 1 single recurrent CSP;83, 89, 96, 97, 98; 2 unusual cases of 3 consecutive CSPs99; 1 molar pregnancy, and 1 case of an
Future obstetric performance after CSP
Our ability to properly counsel women who did not have their uteri removed and desired to become pregnant again has to rely on the reported literature. We therefore reviewed the literature reporting on pregnancies after a successful treatment of a CSP. Sixty-four intrauterine pregnancies after CSP were reported.38, 70, 76, 77, 78, 81, 82, 86, 87, 98, 102, 103, 104, 105, 106, 107 We speculate that these cases (ie, pregnancies and deliveries after CSP) are underreported. We can only hypothesize
The different treatment modalities used in managing CSP
Analyzing the different primary management protocols and approaches led us to our greatest surprise. There were no less than 31 primary approaches to treat the 751 CSPs. These are summarized in Table 2. The sporadic, mostly individual cases and their results were insufficient to enable to draw a clear conclusion as to which was the most effective management protocol leading to the least or no complications. The result of such a large variety of treatment approaches and their different
Treatment complications of CSP
Complications were defined as the immediate or delayed need for a secondary treatment. The most frequent reasons for the additional treatment involved blood loss defined by blood loss requiring transfusion; greater than 200 mL; heavy bleeding; shock; hemoperitoneum or surgical interventions such as laparoscopy, hysteroscopy, laparotomy, hysterectomy, or procedures reported as requiring general anesthesia; or embolization of the uterine arteries. If patients required more than 2 different,
Outcomes after treatments of CSP
Excluding 49 cases of uterine artery embolizations, 14 cases of laparotomies, and 3 elective hysterectomies, which were rendered as planned primary treatment approaches, there were emergency surgeries performed to treat complications. Thirty-six hysterectomies,55, 60, 67, 70, 73, 78, 86, 89, 106, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131 40 laparotomies,45, 46, 50, 51, 52, 54, 60, 67, 68, 69, 95, 96, 99, 120, 121, 128, 129, 130, 132, 133, 134, 135, 136, 137, 138, 139, 140,
Does early intervention yield better outcome?
We wanted to know whether early detection and treatment of CSP would also result in a better outcome. Unfortunately, in only 184 of the 751 cases was the exact gestational age and other accurate, critical, and necessary data determining outcome available. We divided these 184 cases into the following: (1) good outcome if after the initial treatment (single or in combination), they did not have complications (heavy bleeding, embolization, emergency surgery) and (2) complications group, requiring
The true frequency of CSP may be underreported
Based on the number of cases in the literature, it appears that there is an underreporting of CSP. If in 2007 in the United States, there were 4,247,694 deliveries, the CS rate was 32.8%: this represents approximately 1,393,244 cesarean deliveries. Given the reported frequency varies between 1/2000 and 1/2500, it can be estimated that in the United States alone, there should have been 557-696 cesarean scar pregnancies that year. Yet our review of the literature published in the United States
Is it possible to prevent CSP?
Several articles raised the question of preventing a CSP in a future pregnancy by surgical repair of the uterine dehiscence (niche) in patients with previous cesarean deliveries while not pregnant. Ben Nagi et al99 reported on a successful surgical repair of a CD scar; however, the patient had a subsequent chemical pregnancy and 2 additional despite normal intrauterine implantations of the gestational sac. Donnez and colleagues157, 158, 159 performed hysteroscopic repair of the uterine scar in
Are there similarities in the pathogenesis of EPA and CSP?
One of the yet-unanswered questions is whether there is a causative connection between CSP and a later developing PA. It would appear that both have the same pathogenesis. In both cases the placenta implants and invades the myometrium (in the case of placenta accreta) and the scar tissue (in CSP). Because the numbers of both PA and CSP occurrence are steadily increasing, one must consider the relationship between the previously mentioned and the similarly increasing rate of cesarean deliveries.
Conclusions
In studying the literature of PA and CSP, their missed diagnoses, lack of evidence-based treatment approaches, and serious but preventable complications, our review of the cases involving EPA and CSP resulted in the following observations:
- 1
The diagnosis of early PA and/or CSP is difficult. These were often misdiagnosed as low intrauterine pregnancies, cervical pregnancy, or a miscarriage in progress.
- 2
The best diagnostic tool appeared to be high-frequency transvaginal ultrasound, although
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The authors report no conflict of interest.