Systematic review on near miss cases of placenta accreta spectrum disorders: correlation with invasion topography, prenatal imaging, and surgical outcome

Purpose of the article: Placental accreta spectrum (PAS) is the most dangerous iatrogenic complication of cesarean potentially leading to massive intra-partum haemorrhage and death. Despite this, identification of near miss cases of PAS has not been consistently reported in the published literature. The aim of this systematic review was to explore prenatal and surgical characteristics of near miss cases of PAS disorders. Materials and methods: Medline, Embase, CINAHL, SciELO, and Cochrane databases were searched. Only studies including near miss cases of PAS disorders in which a detailed description of the clinical course, severity of placental invasion, role of prenatal imaging, and surgical management were considered eligible for the inclusion in the present systematic review. Random-effect meta-analyses of proportions were used to pool the data. Results: Thirty-four studies were included in the systematic review. The incidence of placenta accreta, increta, and percreta in near miss cases of PAS disorders was 0% (95% CI 0–24.6), 17.3% (95% CI 8.4–28.6) and 82.7% (95% CI 71.4–91.6). S1 invasion, defined as invasion in the upper posterior bladder wall was present in none of the near miss cases of PAS while all included cases showed S2 invasion. Prenatal imaging, either ultrasound or magnetic resonance imaging, detected invasive placenta in 54.4% (95% CI 41.0–67.5). Clinical symptoms occurred in 65.3% (95% CI 52.1–77.4) of near miss cases of PAS before surgery, while the corresponding figures for symptoms occurring during and after surgery were 65.5% (95% CI 52.2–77.5) and 50.0% (95% CI 36.5–63.5) of cases, respectively. Invasion in the inferior part of the lower uterine segment, posterior bladder and parametria was associated with a high risk of morbidity. Conclusion: Near miss cases of PAS are commonly associated with posterior bladder or parametrial invasion and placenta percreta. Further studies are needed in order to identify women affected by PAS disorders at high risk of surgical complications.