A 35 year old G5P1 woman currently pregnant with a 32 week fetus through IVF presents for a routine obstetric visit. Her obstetric history is only significant for a second-trimester low-lying placenta. A transvaginal ultrasound is shown below:
Note the posterior placenta with a linear sonolucent area with color flow Doppler. You admit the patient, give betamethasone and perform frequent fetal heart monitoring. You make a plan to deliver the fetus by emergency C-section if the patient goes into labor, premature rupture of membranes, repetitive variable decelerations refractory to tocolysis, or vaginal bleeding accompanied by fetal heart rate changes. You schedule a C-section at 36 weeks.
Challenge: What's the diagnosis?
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