CSP is a very rare type of ectopic pregnancy with life-threatening complications(10), accounting for 6.1% of ectopic pregnancies among women with a previous history of cesarean delivery(2, 11). Recently, there has been a rise in CSP rates due to the considerably elevated number of cesarean deliveries worldwide(10). Therefore, early diagnosis and effective management and follow-up of CSP is crucial. The exact etiology of this condition remains unknown. A small defect in the uterine incision due to poor healing of the injuries caused by cesarean deliveries, several uterine curettages, and adenomyosis are some of proposed possible mechanisms of CSP development. Also, multiple risk factors such as the number of previous cesarean sections, the interval between the prior cesarean delivery and next pregnancy, the indications for the previous cesarean sections, and the surgery technique have been suggested, though the correlation between these factors and CSP has not been proved yet(12). Delay in the diagnosis and treatment of patients with CSP may be associated with a high risk of uterine rupture, massive hemorrhage, hysterectomy, fertility loss, and maternal mortality(12–14). Diagnosis of CSP is usually difficult and the reported rate of misdiagnosis is significant(15, 16). Sonography is the first-line imaging modality for CSP diagnosis(17). Recent progress in transvaginal and three-dimensional ultrasonography has led to earlier diagnosis and more effective management of a CSP to prevent its catastrophic complications(18). Moreover, it has been indicated that color Doppler imaging may be very useful in early and accurate detection of CSPs(19).
Due to the rarity of CSPs, there has been no consensus for optimal management strategy of CSPs(5, 17). A variety of treatment options including expectant management, medical treatment programs, multiple surgical interventions have been described in the literature(5). In most cases, a combination of these methods has been used to eliminate these ectopic embryos(2). Selecting the most appropriate treatment approach depends on the patient's clinical features, gestational age, size of the mass, serum \({\beta }\)-hCG levels, and clinical experience of the physician(8).
In clinically stable patients with gestational age of less than 8 weeks and the myometrium thickness of less than 2 mm between the CSP and the bladder, medical management is usually applied(10). Although there are no guidelines for optimal follow-up method after the medical management of a CSP, the serum \({\beta }\)-hCG level has been shown to be a suitable marker(10). However, serum \({\beta }\)-hCG levels do not bring about any information on the blood flow of the mass(20). Moreover, some cases have been reported that despite the excessive drop (even to normal values) in \({\beta }\)-hCG levels after medical therapy, the mass did not resolve, resulting in serious consequences(8, 15, 21). In this case, it has been suggested that serial transvaginal Doppler ultrasound examinations may be helpful to investigate the medical management success(10).
The data obtained by the present study showed that serum \({\beta }\)-hCG levels decreased significantly after medical treatment at each time point compared with the previous time point and the baseline (before the treatment) levels, while the RI values of Doppler ultrasound increased significantly. In a study on evaluation of the efficacy of High Intensity Focused Ultrasound (HIFU) in treatment of cesarean section scar pregnancies, Huo et al. observed that four weeks after the treatment RI values were significantly elevated while blood β-hCG levels significantly decreased compared with their pretreatment values(20).
Small sample size and single-index observation were some of the limitations of this study. Further studies with a larger sample size are required to investigate the value of serial Doppler ultrasound examination for follow-up after medical treatment of a CSP.
The results of this study demonstrated that serial Doppler ultrasound examinations can be a useful method to evaluate the success or failure of medical management of CSPs as the increase in RI values occur rapidly after medical treatment and correlate well with blood β-hCG levels’ measurement.