Placenta Accreta Spectrum Disorders and Cesarean Scar Pregnancy Screening: Are we Asking the Right Questions?

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

“…A large number of false-positives in the screening setting (RH) is not a problem if all patients with PAS are detected and if there is an adequate regional referral service where the diagnosis can be confirmed or ruled out. 15 Even in the PAS-RC, it is better to have more false-positives than false-negatives, if there is a strategy to confirm the diagnosis during laparotomy, before implementing invasive interventions.…”

Placenta Accreta Spectrum Disorders: Current Recommendations from the Perspective of Antenatal Imaging

“…If the answer is positive to both questions, the patient should be considered at risk for CSP/PAS at any gestational age and referred to a PAS specialized diagnostic center. 25 Screening for CSP should ideally be performed for all patients with previous CS between 6-9 gestational weeks, when the gestational sac is more related to the uterine scar niche than to the uterine cavity, resulting in better accuracy. 26 The reason for the higher accuracy of ultrasound in detecting CSP in the early compared to the late first trimester relies on the fact that with advancing gestation, the upper pole of the gestational sac grows towards the uterine fundus, thus making assessment of the relationship between the sac and the area of the prior CS scar more difficult to assess.…”

“…For locations with more restricted access to ultrasound, a contingent screening strategy for placenta previa on the 18-24 week scan, with a reassessment of persistent low-lying/placenta previa between 32-34 weeks and referral of patients to referral centers with positive answers for both questions at this moment seems to be more cost-effective and very accurate. 25,29 The disadvantage of this last strategy is the loss of opportunity for counselling and early treatment of CSP cases, which are associated with fewer complications. 30 Diagnostic accuracy for CSP/PAS in specialized diagnostic centers, mainly using ultrasound but relying on nuclear magnetic resonance for specific cases, is usually higher than 90%.…”

Hidden in plain sight: role of residual myometrial thickness to predict outcome of Cesarean scar pregnancy

“…Moreover, first-trimester placenta previa is a powerful supporting finding for the presence of CSP. Lacunae are detected increasingly from 6-7 weeks onward and likewise support the diagnosis 7,13 .…”