Outcome of cesarean scar pregnancy according to gestational age at diagnosis: A systematic review and meta-analysis

Objective: The association between the most severe types of placenta accreta spectrum disorders and caesarean scar pregnancy (CSP) poses the question of whether early diagnosis may impact the clinical outcome of these anomalies. The aim of this study is to report the outcome of cesarean scar pregnancy (CSP) diagnosed in the early (≤9 weeks) versus late (>9 weeks) first trimester of pregnancy. Study design: Medline, Embase and Clinicaltrail.gov databases were searched. Studies including cases of CSP with an early (≤9 weeks of gestation) compared to a late (>9 weeks) first trimester diagnosis of CSP, followed by immediate treatment, were included in this systematic review. The primary outcome was a composite measure of severe maternal morbidity including either severe first trimester bleeding, need for blood transfusion, uterine rupture or emergency hysterectomy. The secondary outcomes were the individual components of the primary outcome. Random-effect meta-analyses were used to combine data. Results: Thirty-six studies (724 women with CSP) were included. Overall, composite adverse outcome complicated 5.9 % (95 % CI 3.5−9.0) of CSP diagnosed ≤9 weeks and 32.4 % (95 % CI 15.7−51.8) of those diagnosed >9 weeks. Massive hemorrhage occurred in 4.3 % (95 % CI 2.3−7.0) of women with early and in 28.0 % (95 % CI 14.1−44.5) of those with late first trimester diagnosis of CSP, while the corresponding figures for the need for blood transfusion were 1.5 % (95 % CI 0.6−2.8) and 15.8 % (95 % CI 5.5−30.2) respectively. Uterine rupture occurred in 2.5 % (95 % CI 1.2−4.1) of women with a prenatal diagnosis of CSP ≤ 9 weeks and in 7.5 % (95 % CI 2.5−14.9) of those with CSP > 9 weeks, while an emergency intervention involving hysterectomy was required in 3.7 % (95 % CI 2.2−5.4) and 16.3 % (95 % CI5.9−30.6) respectively. When computing the risk, early diagnosis of CSP was associated with a significantly lower risk of composite adverse outcome, (OR: 0.14; 95 % CI 0.1−0.4 p < 0.001). Conclusions: Early first trimester diagnosis of CSP is associated with a significantly lower risk of maternal complications, thus supporting a policy of universal screening for these anomalies in women with a prior cesarean delivery although the cost-effectiveness of such policy should be tested in future studies.