Questions and Answers
What is the term for a placenta that protrudes through the uterine serosa?
Which of the following is NOT a risk factor for placenta accreta?
What is the significance of the loss of the normal hypoechoic retroplacental-myometrial interface on sonography?
What is the characteristic of the blood flow in placenta increta or placenta percreta on color Doppler ultrasound?
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What is the term for a placenta that is abnormally adherent to the uterine wall after delivery?
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What is the significance of the presence of focal exophytic masses on sonography?
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What is the characteristic of placental lakes on sonography?
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What is the term for a placenta that invades the myometrium more deeply?
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What is the significance of the demonstration of vessels crossing the placental-myometrial disruption site on color Doppler ultrasound?
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What is the significance of the absence of the normal subplacental venous flow on color Doppler ultrasound?
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Study Notes
Placenta Anomalies
- Placenta accreta: a placenta that is abnormally adherent to the uterine wall after delivery
- Placenta increta: a placenta that invades the myometrium more deeply than accreta
- Placenta percreta: a placenta that protrudes through the uterine serosa, at least in part
Risk Factors for Placenta Accreta
- Prior uterine surgery, with increasing risk with increasing number of prior cesarean deliveries
- Placenta previa
- Unexplained elevated maternal serum alpha-fetoprotein (MS-AFP)
- Increased maternal cell-free placental lactogen
- Advancing maternal age
Characteristics of Placenta Accreta
- Presence of a coexisting placenta previa in the majority of cases
- The adherent portion of the placenta is often low in the uterus, in the region of a prior cesarean scar
Sonographic Findings of Placenta Accreta
- Loss of the normal hypoechoic retroplacental-myometrial interface
- Thinning or disruption of the hyperechoic subvesicular uterine myometrium/serosa
- Presence of focal exophytic masses
- Numerous placental lakes
Color Doppler Ultrasound Findings
- Diffuse lacunar blood flow throughout the placenta
- Dilated vascular channels between the placenta and bladder or cervix
- Absence of the normal subplacental venous flow
- Demonstration of vessels crossing the placental-myometrial disruption site
Characteristics of Placenta Increta or Percreta
- Greatly increased vascular lacunae with turbulent or “tornado” blood flow
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Description
This quiz covers placenta abnormalities, including placenta accreta, increta, and percreta, and their risk factors, such as prior uterine surgery and placenta previa.