Guideline sources The following summarized guidelines for the evaluation and management of placenta accreta spectrum are prepared by our editorial team based on guidelines from the Royal College of Obstetricians and Gynaecologists (RCOG 2019) and the American College of Obstetricians and Gynecologists (ACOG/SMFM 2018). 1 2 Guidelines 1. Screening and diagnosis Diagnosis: recognize that antenatal diagnosis of placenta accreta spectrum is crucial in planning its management and has been shown to reduce maternal morbidity and mortality. B 2. Classification and risk stratification Risk factors: As per ACOG 2019 guidelines: https://web.pathway.md/diseases/recRvXuzqk4ZCMsQk 1/5 6/29/23, 11:12 PM Placenta accreta spectrum Pathway Recognize that the major risk factors for placenta accreta spectrum are history of accreta in a previous pregnancy, previous Cesarean delivery (rising with the number of previous C- sections) and other uterine surgery, including repeated endometrial curettage. B Inform patients requesting elective Cesarean delivery for non-medical indications about the risk of placenta accreta spectrum and its consequences for subsequent pregnancies. B As per RCOG 2019 guidelines, recognize that previous Cesarean delivery, anterior low-lying placenta or placenta previa are associated with a higher risk of placenta accreta spectrum. B 3. Diagnostic investigations Ultrasound: As per RCOG 2019 guidelines, recognize that ultrasound is highly accurate when performed by a skilled operator with experience in diagnosing placenta accreta spectrum. B Show 2 more As per ACOG 2018 guidelines, recognize that the absence of ultrasound findings does not preclude a diagnosis of placenta accreta spectrum, thus clinical risk factors remain equally important as predictors of placenta accreta spectrum by ultrasound findings. A Magnetic resonance imaging: As per RCOG 2019 guidelines: Recognize that the diagnostic value of MRI and ultrasound imaging in detecting placenta accreta spectrum is similar when performed by experts. B Consider obtaining MRI to complement ultrasound for the assessment of the depth of invasion and lateral extension of myometrial invasion, especially with posterior placentation and/or in patients with ultrasound signs suggesting parametrial invasion. C As per ACOG 2018 guidelines, do not obtain MRI as the preferred imaging modality for the initial evaluation of patients with possible placenta accreta spectrum. D 4. Medical management Setting of care: As per RCOG 2019 guidelines, ensure care of patients with placenta accreta spectrum is provided by a multidisciplinary team in a specialist center with expertise in diagnosing and managing invasive placentation. B As per ACOG 2018 guidelines, ensure a standardized approach with a comprehensive multidisciplinary care team for the management of patients with placenta accreta spectrum. B Expectant management: As per RCOG 2019 guidelines, consider leaving the placenta in situ if elective peripartum hysterectomy is unacceptable in patients desiring uterine preservation or considered inappropriate by the surgical team. C Show 2 more https://web.pathway.md/diseases/recRvXuzqk4ZCMsQk 2/5 6/29/23, 11:12 PM Placenta accreta spectrum Pathway As per ACOG 2018 guidelines, consider offering conservative management or expectant approaches only in carefully selected patients with placenta accreta spectrum after detailed counseling about the risks, uncertain benefits, and efficacy as an investigational method. C 5. Therapeutic procedures Blood product transfusion: As per RCOG 2019 guidelines, discuss additional possible interventions in case of massive hemorrhage, including cell salvage if available. B As per ACOG 2018 guidelines, use a range of 1:1:1 to 1:2:4 strategy of packed RBCs:FFP:platelets in patients with hemorrhage. A Interventional radiology: insufficient evidence to recommend the use of interventional radiology for the routine management of patients with placenta accreta spectrum. I Show 2 more Setting of delivery: As per RCOG 2019 guidelines: Ensure delivery of patients with placenta accreta spectrum takes place in a specialist center with logistic support for immediate access to blood products, adult ICU and neonatal ICU by a multidisciplinary team with expertise in complex pelvic surgery. B Manage elective delivery of patients with placenta accreta spectrum by a multidisciplinary team including senior anesthetists, obstetricians and gynecologists with appropriate experience in managing the condition and other surgical specialties if indicated. Involve the most senior clinicians available in an emergency situation. B As per ACOG 2018 guidelines, ensure that patients with suspected placenta accreta spectrum diagnosed in the antenatal period based on imaging or clinical acumen deliver at a level III or IV center with considerable experience whenever possible to improve outcomes. B Timing of delivery: As per RCOG 2019 guidelines: Develop a contingency plan for emergency delivery in partnership with patients, including the use of an institutional protocol for the management of maternal hemorrhage, once the diagnosis of placenta accreta spectrum is made. B Plan delivery at 35+0 to 36+6 weeks of gestation for the best balance between fetal maturity and the risk of unscheduled delivery in the absence of risk factors for preterm delivery in patients with placenta accreta spectrum. B As per ACOG 2018 guidelines, consider offering delivery at 34 to 35 weeks of gestation for scheduled Cesarean delivery or hysterectomy absent extenuating circumstances in stable patients. Consider offering early delivery in patients with persistent bleeding, preeclampsia, labor, rupture of membranes, fetal compromise, or if developing maternal comorbidities. B 6. Perioperative care Considerations for anesthesia: https://web.pathway.md/diseases/recRvXuzqk4ZCMsQk 3/5 6/29/23, 11:12 PM Placenta accreta spectrum Pathway Choose anesthetic technique for C-section in patients with placenta accreta spectrum by the anesthetist conducting the procedure in consultation with the patient before surgery. B Inform patients that the surgical procedure can be performed safely with regional anesthesia, but it may be necessary to convert to general anesthesia if required and ask to consent to this. B 7. Surgical interventions Cesarean hysterectomy: prefer performing C-section hysterectomy with the placenta left in situ over attempting to separate it from the uterine wall. B Uterus-sparing surgery: consider performing uterus-preserving surgery, including partial myometrial resection if the extent of the placenta accreta is limited in depth and surface area, and the entire placental implantation area is accessible and visualized (completely anterior, fundal or posterior without deep pelvic invasion). C Show 2 more Ureteric stenting: insufficient evidence to recommend the routine use of ureteric stents in patients with placenta accreta spectrum. Consider using ureteric stents when the urinary bladder is invaded by placental tissue. I 8. Specific circumstances Patients with placenta accreta diagnosed intrapartally: Delay C-section until the appropriate staff and resources have been assembled and adequate blood products are available if at the time of an elective repeat C-section, where both mother and baby are stable, it is immediately apparent that placenta percreta is present on opening the abdomen. Consider closing the maternal abdomen and urgently transferring to a specialist unit for delivery. B Leave placenta in situ and perform an emergency hysterectomy if unsuspected placenta accreta spectrum diagnosed after the birth of the baby. B 9. Patient education General counseling: Ensure that any patients giving consent for C-section understands the risks associated with C-section in general, and the specific risks of placenta accreta spectrum in terms of massive obstetric hemorrhage, increased risk of lower urinary tract damage, the need for blood transfusion and the risk of hysterectomy. B Inform patients that the surgical procedure can be performed safely with regional anesthesia, but it may be necessary to convert to general anesthesia if required and ask to consent to this. B References https://web.pathway.md/diseases/recRvXuzqk4ZCMsQk 4/5 6/29/23, 11:12 PM Placenta accreta spectrum Pathway 1. Society of Gynecologic Oncology, American College of Obstetricians and Gynecologists and the Society for Maternal Fetal Medicine, Alison G Cahill et al. Placenta Accreta Spectrum. Am J Obstet Gynecol. 2018 Dec;219 6 B2 B16. Open 2. Jauniaux E, Alfirevic Z, Bhide AG et al. Placenta Praevia and Placenta Accreta: Diagnosis and Management: Green-top Guideline No. 27a. BJOG. 2019 Jan;126 1):e1-e48. Open https://web.pathway.md/diseases/recRvXuzqk4ZCMsQk 5/5