Research progress on pathogenesis of placenta accreta spectrum / 中华围产医学杂志

Placenta accreta spectrum (PAS) refers to the condition that placental trophoblast cells directly invade the myometrium,which is one of the most dangerous complications in obstetrics,but the pathogenesis has not been clarified.In recent years,the incidence of PAS was increasing,which has become the major reason leading to postpartum hemorrhage,perinatal emergency hysterectomy and maternal death.Available studies suggested that the occurrence of PAS was related to the following three interconnected factors:the loss of decidual membrane,enhanced trophoblast invasiveness and abnormal recasting of uterine spiral artery.This review focused on these three factors and tried to illustrate the pathophysiology of PAS.

Risk factors and sonographic findings associated with the type of placenta accreta spectrum disorders / 中华妇产科杂志

Objective To evaluate the risk factors and sonographic findings of pregnancies complicated by placenta increta or placenta percreta. Methods Totally, 2219 cases were retrospectively analyzed from 20 tertiary hospitals in China from January 2011 to December 2015. The data were collected based on the original case records. All cases were divided into two groups, the placenta increta (PI) group (79.1％, 1755/2219) and the placenta percreta (PP) group (20.9％, 464/2219), according to the degree of placental implantation. The risk factors and sonographic findings of placenta increta or percreta were analyzed by uni-factor and logistic regression statistic methods. Results The risk factors associated with the degree of placental implantation were age, gravida, previous abortion or miscarriage, previous cesarean sections, and placenta previa (all P<0.05), especially, previous cesarean sections (χ2=157.961) and placenta previa (χ2=91.759). Sonographic findings could be used to predict the degree of placental invasion especially the boundaries between placenta and uterine serosa, the boundary between placenta and myometrium, the disruption of the placental-uterine wall interface and loss of the normal retroplacental hypoechoic zone(all P<0.01). Conclusions Previous cesarean sections and placenta previa are the main independent risk factors associated with the degree of placenta implantation. Ultrasound could be used to make a prenatal suggestive diagnosis of placenta accreta spectrum disorders.