Caesarean scar pregnancy (CSP) is the rarest form of ectopic pregnancy and can be associated to serious and life threatening obstetric complications. The incidence of CSP varies from 1 in 1800 to 1 in 2226 pregnancies  and accounts for 6% of ectopic pregnancies in women with prior cesarean deliveries . Given its location and possibility of growth with associated normally increasing titres of beta-hCG, a high suspicion index remains the only efficient way to identify and manage this life threatening obstetric condition on time. Even though the main cause of CSP is not known, in literature, it has been associated to history of uterine trauma, caesarean section , invitro fertilization, manual placental removal, adenomyosis and myomectomy [1, 5, 9].
In most cases of CSP, the gestation sac is usually completely surrounded by myometrium and the fibrous tissue of the scar, quite separate from the endometrial cavity . These forms are generally termed “intramural pregnancies” (that is, completely confined to the myometrium) as opposed to the other forms which develop without total confinement to the myometrium . The most efficient and readily available tool for early diagnosis is transvaginal ultrasound. Suggested sonographic criteria to be considered when making diagnosis of CSP in literature include: empty uterine cavity; location of trophoblast mainly between bladder and anterior uterine wall; thin or absent layer of myometrium between the gestational sac and the bladder; identification of a discontinuity in the anterior wall of the uterus on a sagittal view running through the amniotic sac and an empty endo-cervical canal [10, 11]. No classical treatment methods have been described in literature but treatment methods range from close monitoring to viability and term to conservative and radical surgery in case of uterine rupture [2, 12].
In our case, the patient had undergone two caesarean sections with a successful trial of the two scars and a dilatation and curettage for an incomplete abortion. The trial of the double scar and the subsequent dilatation and curettage might have compromised the integrity of the caesarean scar thereby exposing her to CSP. In CSP, it is thought that implantation villi find their way into the myometrium through a microtubular tract between the caesarean section scar and the endometrial canal . The placenta and the conceptus were totally expulsed from the uterine opening with an intact posterior uterine wall.
Most cases of CSP are usually diagnosed in the first trimester. Patients are generally amenorrheic women with painless vaginal bleeding early in pregnancy (39%), mild abdominal pain or discomfort (16%) [1, 5]. In case of rupture, patients will present with severe acute pain of sudden onset and profuse bleeding and hypovolemic shock. However, 9% of patients with non-ruptured forms might present just with abdominal pains and may be asymptomatic with incidental diagnosis in 37% of cases . This constitutes the diagnostic dilemma as none of these signs directly point to caesarean scar pregnancy as the closest possible diagnosis. This therefore calls on a high index of suspicion of CSP especially in women presenting with any of the above symptoms and any of the risk factors. On suspicion of CSP radiological evaluation is mandatory . In most cases without rupture or onset of rupture, clinical examination is usually unremarkable. The uterus and the abdomen are usually tender in case of rupture . Failure of diagnosis and extension into the second trimester is usually associated with a higher risk of rupture and haemorrhage. It was the case with the client as the diagnosis was only made when the life of the patient was seriously threatened.
In the above presented case, our patient had presented twice with mild pervaginal bleeding in the first trimester which was managed with injectable progesterone. No first trimester ultrasound was done by the patient because of financial barriers. The influence of the low income setting here on the health of the patient is clear. This is a cause for concern as most pregnant women in our setting start antenatal consultations only in the second trimester and the ultrasounds are done only in the late second trimester. The very rare nature of ectopic pregnancies in the developed world has also been associated to missed and mismanaged cases of CSP even when first trimester ultrasound scans are readily available . Early diagnosis and management of this life threatening condition is therefore even more impeded in a resource-limited setting given that the access of pregnant women to ultrasound scans is still limited.
The working diagnosis (threatened abortion due to malaria or asymptomatic bacteriuria with acute appendicitis in pregnancy as differential) was considered given the very low suspicion index of CSP within the team. This low suspicion index and the absence of the ultrasonographer allowed for progression of the condition to its severe and life threatening stage. In case of rupture, medical treatment with methotrexate or curettage is not a suitable option. Emergency laparotomy with resection of the ectopic and repair of the uterus or hysterectomy are suitable options. In our case, given the future fertility desire expressed by the couple and peroperative findings, we completed resection of the ectopic and repaired the uterine opening.
Caesarean scar pregnancy remains a very rare obstetric condition. Late diagnosis of this condition can be associated with serious life threatening obstetric complications. Given the rare nature ectopic pregnancies and more specifically CSP, clinicians should have a high index of suspicion especially in amenorrheic women with risk factors. First trimester ultrasonography remains indispensable in the appropriate screening for such conditions especially in clients presenting with risk factors. Improving access to prenatal services (while emphasizing on the need to take up these services early in pregnancy and systematically meeting competent ultrasonographers in the first trimester especially in patients with risk factors for CSP) could go a long way to improve the condition and the prognosis of patients with CSP.