From the Guidelines
The condition of the placenta can be affected by placenta accreta spectrum disorder (PASD), a condition where the placenta abnormally adheres to the myometrium, which can lead to severe and life-threatening hemorrhage during delivery. The placenta is an organ that develops during pregnancy to provide oxygen and nutrients to the growing fetus while removing waste products from the baby's blood. Placenta accreta spectrum disorder (PASD) refers to a variety of potential clinical complications that may result from abnormal placental implantation, including placenta accreta, placental increta, and placenta percreta 1.
Risk Factors
The risk factors for PASD include prior cesarean delivery, placenta previa, advanced maternal age, high gravidity or parity, in vitro fertilization, prior uterine surgery and trauma, prior postpartum hemorrhage, Asherman syndrome, uterine anomalies, smoking, and hypertension 1. The incidence of PASD has increased over past decades, with the risk increasing 7-fold after one prior cesarean delivery to 56-fold after 3 cesarean deliveries 1.
Diagnosis and Management
Accurate antenatal diagnosis of PASD is crucial to plan for an appropriate delivery strategy at an experienced center to reduce maternal morbidity 1. The American Congress of Obstetricians and Gynecologists (ACOG) and the International Federation of Obstetrics and Gynecology (FIGO) recommend planned cesarean delivery with or without hysterectomy depending on the suspected severity of PASD around 34 to 38 weeks 1. High-risk patients should be followed closely by experienced centers where emergent mobilization of a multidisciplinary team needed for a scheduled or unscheduled delivery is feasible 1.
Key Considerations
Key considerations in the management of PASD include:
- Careful planning of the timing of delivery to achieve optimal fetal maturity and avoid the chance of spontaneous labor
- Having a contingency plan for emergent delivery in place
- Obtaining radiologic and clinical data when PASD is first suspected to formulate an appropriate delivery strategy and contingency plan
- Close follow-up of high-risk patients by experienced centers 1.
From the Research
Condition of the Placenta
The condition of the placenta can be affected by various factors, including placental abruption, placenta previa, and abnormal placentation.
- Placental abruption is a complete or partial separation of the placenta from the uterine decidua, which can cause vaginal bleeding, abdominal pain, uterine contractions, and abnormalities in the fetal heart rate tracing 2, 3.
- The pathophysiology of placental abruption remains incompletely understood, but it is thought to involve overlapping processes that contribute to premature placental separation 2.
- Placenta previa is an important and potentially life-threatening cause of bleeding, which can be identified during routine second-trimester ultrasound 4.
- Abnormal placentation, including placenta previa, placenta accreta, and vasa previa, can cause significant maternal and perinatal morbidity and mortality 5.
Prevalence and Risk Factors
- Placental abruption occurs in 0.4% to 1.0% of all pregnancies 2, while placenta previa occurs in a smaller percentage of pregnancies 4.
- Risk factors for placental abruption include uterine malformations, pPROM, placenta previa spectrum, and oligohydramnios 6.
- Key risk factors for placenta previa include prior cesarean delivery, advanced maternal age, and smoking 4.
Diagnosis and Management
- The diagnosis of placental abruption and placenta previa can be made using ultrasound and fetal heart rate tracings 2, 3, 4.
- Management of placental abruption and placenta previa depends on gestational age, fetal status, and maternal hemodynamic stability 2, 3, 4.
- A planned cesarean delivery is recommended in cases of placenta previa that persist into the late third trimester 4.