Prenatal identification of invasive placentation using ultrasound: systematic review and meta-analysis

OBJECTIVE: The accuracy of prospective sonographic prenatal detection of invasive placentation is unclear. The objective of this study was to conduct a systematic review and meta-analysis to assess the performance of ultrasound in at-risk women for prenatal identification of invasive placentation. METHODS: MEDLINE, EMBASE, The Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects (DARE) and The Cochrane Central Register of Controlled Trials (CENTRAL) were searched using the search terms 'placenta accreta', 'placenta increta', 'placenta percreta', 'ultrasound', 'magnetic resonance imaging (MRI)', 'invasive placenta' and 'infiltrative placenta'. Two authors independently abstracted data from the articles. Sensitivity, specificity, positive and negative likelihood ratios (LR+ and LR-), the diagnostic odds ratio (DOR) and their 95% CIs for each study were calculated. Forest plots and summary receiver-operating characteristics curves were produced. Between-study heterogeneity was explored both graphically and statistically. The MOOSE (meta-analysis of observational studies in epidemiology) guidelines were followed. RESULTS: Twenty-three studies involving 3707 pregnancies at risk for invasive placentation were included. The overall performance of ultrasound for the antenatal detection of invasive placentation was as follows: sensitivity, 90.72 (95% CI, 87.2-93.6)%; specificity, 96.94 (95% CI, 96.3-97.5)%; LR+, 11.01 (95% CI, 6.1-20.0); LR-, 0.16 (95% CI, 0.11-0.23); and DOR, 98.59 (95% CI, 48.8-199.0). Among the different ultrasound signs, color Doppler had the best predictive accuracy (sensitivity, 90.74 (95% CI, 85.2-94.7)%; specificity, 87.68 (95% CI, 84.6-90.4)%; LR+, 7.77 (95% CI, 3.3-18.4); LR-, 0.17 (95% CI, 0.10-0.29); and DOR, 69.02 (95% CI, 22.8-208.9)). CONCLUSIONS: Ultrasound has a high accuracy for prenatal diagnosis of disorders of invasive placentation in high-risk women. The use of color Doppler improves the test performance.