placenta accreta

Placenta accreta spectrum

Placenta accreta spectrum (PAS), also called morbidly adherent placenta is a medical condition that occurs when all or part of the placenta attaches abnormally to the myometrium (the muscular layer of the uterine wall) during pregnancy. This condition was first documented in medical literature in 1927. Three grades are defined by the International Federation of Gynecology and Obstetrics (FIGO), which were initially named accreta, increta, and percreta in order of severity. Because of abnormal attachment to the myometrium, PAS is associated with an increased risk of massive hemorrhaging, heavy bleeding, at the time of attempted vaginal delivery. This leads many to deliver through a caesarean section. The need for transfusion of blood products is frequent, and a surgical removal of the uterus (hysterectomy) is sometimes required to control life-threatening bleeding. Rates of placenta accreta are increasing, and are even higher in developing countries. A 2016 study found that placenta accreta affected 1 in 272 women with a birth-related hospital discharge diagnosis in the US. Furthermore, the increase in PAS prevalence over decades has been a major cause of morbidity and mortality among pregnant women, and has been a main factor in the increase of caesarean deliveries.