【Abstract】 objective To investigate the value of prenatal ultrasound signs and high-risk factors in the diagnosis of placenta accreta spectrum without placenta previa. Methods A retrospective analysis was performed on placenta accreta spectrum patients without placenta previa diagnosed during delivery or by cesarean section in Beijing Obstetrics and Gynecology Hospital affiliated to Capital Medical University from September 2020 to December 2021

The risk factors

typical prenatal ultrasound signs and pregnancy outcomes were summarized and analyzed.Results There were 66 cases of placenta accreta spectrum diagnosed by clinical diagnosis or placenta pathology

13 cases had incomplete clinical data or non-standard ultrasound images

45 cases with placenta previa and 8 cases without placenta previa.Among the 8 cases of placenta accreta spectrum without placenta previa

3 cases were placental accreta

4 cases were placental increta

and 1 case was placental percreta.Prenatal ultrasound suggested placenta accreta spectrum in 6 cases

and missed diagnosis in 2 cases.Among the 6 cases with a history of cesarean section

5 had a history of intrauterine operation

and 2 had no history of cesarean operation

but all had a history of intrauterine operation.Postpartum hemorrhage occurred in 7 cases (≥1000ml) and 800ml in 1 case; One patient underwent total hysterectomy

and 7 patients retained uterus.The typical ultrasound signs of placenta implantation were found in 6 cases during prenatal screening

the abnormality of the uterine - bladder interface was found in all patients

mainly manifested by thinning of the myometrium and Loss of clear zone

All 3 cases had placental lacunae and bridging vessels at the uterine - bladder interface.2 cases did not retain images according to prenatal ultrasound screening standards for placental accreta spectrum

and no typical signs of placental implantation were detected.Conclusions Therefore

in the process of prenatal examination

the screening of high-risk factors combined with the prenatal ultrasound screening standards for placenta accreta spectrum disease

the application of two-dimensional gray scale ultrasound and two-dimensional color Doppler ultrasound in the comprehensive examination of placenta is of great value in the diagnosis of placental implantation diseases without placenta previa.