Placenta Accreta Spectrum Disorders

Knowledge Gaps in Anesthesia Care

Christine M. Warrick, MD; John C. Markley, MD, PhD; Michaela K. Farber, MD, MS; Mrinalini Balki, MBBS, MD; Daniel Katz, MD; Philip E. Hess, MD; Cesar Padilla, MD; Jonathan H. Waters, MD; Carolyn F. Weiniger, MB, ChB; Alexander J. Butwick, MBBS, FRCA, MS


Anesth Analg. 2022;135(1):191-197. 

In This Article

Abstract and Introduction


Placenta accreta spectrum (PAS) disorder is a potentially life-threatening condition that can occur during pregnancy. PAS puts pregnant individuals at a very high risk of major blood loss, hysterectomy, and intensive care unit admission. These patients should receive care in a center with multidisciplinary experience and expertise in managing PAS disorder. Obstetric anesthesiologists play vital roles in the peripartum care of pregnant patients with suspected PAS. As well as providing high-quality anesthesia care, obstetric anesthesiologists coordinate peridelivery care, drive transfusion-related decision making, and oversee postpartum analgesia. However, there are a number of key knowledge gaps related to the anesthesia care of these patients. For example, limited data are available describing optimal anesthesia staffing models for scheduled and unscheduled delivery. Evidence and consensus are lacking on the ideal surgical location for delivery; primary mode of anesthesia for cesarean delivery; preoperative blood ordering; use of pharmacological adjuncts for hemorrhage management, such as tranexamic acid and fibrinogen concentrate; neuraxial blocks and abdominal wall blocks for postoperative analgesia; and the preferred location for postpartum care. It is also unclear how anesthesia-related decision making and interventions impact physical and mental health outcomes. High-quality international multicenter studies are needed to fill these knowledge gaps and advance the anesthesia care of patients with PAS.


Placenta accreta spectrum (PAS) disorder is a highly morbid condition characterized by abnormal adherence of the placenta to the uterine wall. The incidence of PAS has increased markedly over time, from between 1 in 2510 and 1 in 4017 between the 1970s and 1980s to 1 in 533 between 1982 and 2002.[1] More recent data from the Nationwide Inpatient Sample, a large US hospitalization database, reported that the incidence was 1 in 272 between 1998 and 2011.[2] The escalating incidence of PAS since the 1970s is related to the marked increase in the US cesarean delivery rate from the early to late 2000s.[3]

Patients with a PAS disorder are at substantial risk of major peripartum complications, including massive blood loss, hysterectomy, and intensive care unit admission.[4] Clinical guidelines published by The American College of Obstetricians and Gynecologists, The International Society for Abnormally Invasive Placenta, and The International Federation of Gynecology and Obstetrics (FIGO) highlight the importance of a multidisciplinary team for case management.[5–7]

As a key member of a multidisciplinary team, an anesthesiologist has several important roles. In addition to providing high-quality anesthesia care, anesthesiologists coordinate peridelivery care with the multidisciplinary team (which includes surgeons, transfusion medicine specialists, and critical care physicians), oversee transfusion-related decision making and manage postpartum analgesia. Outcomes in patients with PAS may also be optimized through input provided by an anesthesiologist with training and experience in peridelivery and perioperative medical care.[8]

The extent to which anesthetic and analgesic-related practices and interventions influence maternal and neonatal outcomes in patients with PAS is unclear. Most studies of anesthesia practices contain relatively small samples from single obstetric centers.[9–18] The lack of high-quality data from population-based cohorts and randomized trials may explain why there is a lack of consensus statements and guidelines. Consequently, anesthesia and analgesia-related recommendations are predominantly based on expert opinion.[19,20]

In this Special Article, we highlight knowledge gaps related to the anesthetic care of patients with PAS and research needed to fill these gaps. Filling these gaps will provide sufficient evidence to inform future guidelines and consensus statements for anesthesia care.