Accreta placentation

Effective screening for placenta accreta can be provided in the first trimester of pregnancy. A study involving more than 20,000 pregnancies reported that at 11-13 weeks’ gestation, about 5% of women had a history of previous uterine surgery and low lying placenta. These women were examined in a specialist PAS clinic at 12-16 weeks’ gestation and in all 13 cases of placenta accreta in the population the diagnosis was made at this early stage in pregnancy.

At least one marker was found in all cases of placenta accreta, in one third of cases of placenta previa and in about 10% of cases without placenta previa. The most common markers, found in both the cases of placenta accreta and those without were intraplacental lacunar spaces and non-visible cesarean section scar. At least three markers were found in all 13 cases of placenta accreta and in 1 of the 1000 cases without placenta accreta, giving a false positive rate of 0.1%.