Placenta Accreta Spectrum Prenatal Diagnosis Performance: Are Ultrasound False-positive Results Acceptable in Limited-resources Settings?

Desempenho do diagnóstico pré-natal do espectro da placenta acreta: Os resultados falso-positivos do ultrassom são aceitáveis em ambientes com recursos limitados?

Objective  The immediate referral of patients with risk factors for placenta accreta spectrum (PAS) to specialized centers is recommended, thus favoring an early diagnosis and an interdisciplinary management. However, diagnostic errors are frequent, even in referral centers (RCs). We sought to evaluate the performance of the prenatal diagnosis for PAS in a Latin American hospital.

Methods  A retrospective descriptive study including patients referred due to the suspicion of PAS was conducted. Data from the prenatal imaging studies were compared with the final diagnoses (intraoperative and/or histological).

Results  A total of 162 patients were included in the present study. The median gestational age at the time of the first PAS suspicious ultrasound was 29 weeks, but patients arrived at the PAS RC at 34 weeks. The frequency of false-positive results at referring hospitals was 68.5%. Sixty-nine patients underwent surgery based on the suspicion of PAS at 35 weeks, and there was a 28.9% false-positive rate at the RC. In 93 patients, the diagnosis of PAS was ruled out at the RC, with a 2.1% false-negative frequency.

Conclusion  The prenatal diagnosis of PAS is better at the RC. However, even in these centers, false-positive results are common; therefore, the intraoperative confirmation of the diagnosis of PAS is essential.

Keywords
placenta accreta; ultrasonography; false positive; prenatal ultrasonic diagnosis; operative surgical procedure