AFJOG

REVIEW INTRODUCTION Cesarean scar pregnancy (CSP) occurs when a blastocyst partially or wholly implants in a myometrial defect or scar tissue from a previous caesarean delivery. CSP accounts for 0.4% of all pregnancies and 6% of ectopic pregnancies among patients who have had a prior cesarean section, with a recurrence rate of 15.6%. Although the overall incidence rate of CSP seems low, it can result in serious maternal complications if not recognised early and managed appropriately. 1 The rising trend in the number of cesarean sections globally will predictably increase the incidence of CSP even in low-resource settings. 2 Early pregnancy clinics are not widely accessible in low-resource settings. In addition, cultural, socioeconomic and health system related factors tend to preclude women in low-resource settings from early initialisation of antenatal care. Therefore, women with CSP in these settings are more likely to present with CSP associated complications. 3-5 CSP may present with features suggestive of threatened or incomplete miscarriage or a ruptured tubal ectopic pregnancy that can inadvertently lead to less appropriate interventions and adverse outcomes, especially if the patient presents at a primary healthcare clinic or district hospital. 6 However, the increasing availability of point-of-care ultrasound can assist in the correct diagnosis, triage, appropriate referral for care and choice of the treatment in patients with CSP, to enhance preservation of fertility and early conception if desired. In this article, we discuss types of CSP, clinical and ultrasound features, and the factors associated with successful outcomes for each treatment modality for CSP. PATHOGENESIS OF CSP Although the pathological mechanisms of CSP are not yet fully understood. It has been suggested that higher transverse uterine incisions close to the upper segment secondary to a poorly formed lower segment, has been associated with an increased risk of CSP. 7 Uterine retroversion has also been reported as a possible mechanism, suggesting reduced perfusion at the hysterotomy site results in ischaemia and relative hypoxia. The scar tissue may have micro or macro defects through which the blastocyst may implant. In addition, the relative hypoxia of the scar tissue and deficient layer of Nitabuch may predispose to deeper penetration of trophoblastic villi into the myometrium, serosa and bladder. 8-10 CLINICAL FEATURES OF CSP CSP may be asymptomatic in 37% of cases, 39% of patients may present with light vaginal bleeding, and 29% with mild abdominal pains. 11, 12 Symptoms may be nonspecific and a high index of suspicion is needed in all pregnant patients with a previous Caesarean delivery. 6 Pregnancies carried to the second and third trimester are likely to present with clinical features of placenta accreta spectrum (PAS) and uterine rupture. They may also remain asymptomatic, but are more prone to severe intrapartum or postpartum haemorrhage and hysterectomy as a result of PAS, especially those implanted within the CSP niche. 6,13 ULTRASOUND FEATURES OF CAESAREAN SCAR PREGNANCY Ultrasound should be used as the primary modality for diagnosing caesarean scar pregnancy, with high–resolution transvaginal ultrasound considered the gold standard. 6 Ultrasound examination can be used to grossly categorize CSP into two types. The first type is the endogenic or “on the scar” type, which comprises pregnancies where the gestational sac implants on the caesarean section scar without embedding deeply into the myometrium, but instead grow inwards. The second type is the exogenic type, comprising pregnancies deeply embedded within the caesarean scar in the anterior myometrial wall, with the gestational sac sometimes causing a bulge towards the uterine serosa or bladder. These are thought to result from implantation in a defect within a poorly healed caesarean scar, also referred to as the “in the niche” type. 15 L Madikizela 1 , CN Gubu-Ntaba 1 , VMpumlwana 1 , SB Phinzi 1 , and S Joseph 2 , CB Businge 1 ‡ 1 Department of Obstetrics and Gynaecology, Nelson Mandela Academic Hospital / Walter Sisulu University, Nelson Mandela Drive, Mthatha, South Africa 2 Department of Internal Medicine, Nelson Mandela Academic Hospital / Walter Sisulu University, Nelson Mandela Drive, Mthatha, South Africa CORRESPONDENCE: CB Businge| Email: cbusinge@wsu.ac.za/ cbusingae@gmail.com Caesarean Scar Pregnancy: factors associated with successful outcomes of treatment modalities and implications for peripheral health care facilities and low-resource settings ABSTRACT The risk of caesarean scar pregnancy (CSP), which is associated with the increasing rate of caesarean delivery raises concern, due to the severe morbidity associated with CSP, especially when not diagnosed and appropriately managed in the first trimester. The increasing availability of point-of-care ultrasound, even at lower-level facilities, provides an opportunity for screening and early management of CSP, as recommended by the Society of Maternal and Foetal Medicine. Equipping healthcare workers at peripheral institutions with diagnostic skills, knowledge of the various treatment options and clinical features associated with the success of each option, may improve correct diagnosis, resulting in appropriate treatment and prompt referral when indicated. This can help foster the primary goals of preventing severe morbidity as well as preserving fertility for patients presenting with CSP. African Journal of Obstetrics and Gynaecology | Volume 1 | Issue 2 | 2023 | 05