Analysis of the predictable variables for placenta accreta without placenta previa

Area of Science:

• Obstetrics and Gynecology
• Maternal-Fetal Medicine
• Diagnostic Imaging

Background:

• Placenta accreta (AP) can lead to severe hemorrhage, necessitating hysterectomy.
• Distinguishing AP from normal placental implantation is crucial for surgical planning.
• This study focuses on AP in the absence of placenta previa, a less commonly studied scenario.

Purpose of the Study:

• To identify predictive maternal and ultrasonographic variables for placenta accreta (AP) in pregnancies not complicated by placenta previa.
• To improve the preoperative diagnosis of AP in specific clinical contexts.

Main Methods:

• Prospective cohort study conducted from 2008 to 2010.
• Inclusion criteria: singleton delivery after 36 weeks' gestation, without placenta previa.
• Evaluation of maternal history and ultrasonographic findings at delivery admission.

Main Results:

• Six cases (0.2%) of placenta accreta without placenta previa were identified in 2834 subjects.
• Placenta accreta was significantly associated with a history of uterine surgery (1.9% vs. 0.1%, p < 0.001).
• Absence of a retroplacental clear zone (33% vs. 0.1%, p < 0.001) and placenta location on a uterine scar were also strong predictors.

Conclusions:

• A prior history of uterine surgery is a significant risk factor for placenta accreta.
• Absence of a retroplacental clear zone on ultrasound is highly suggestive of placenta accreta.
• Placental location over a uterine scar is another key ultrasonographic finding associated with AP in the absence of placenta previa.