Presentation
Placental re-assessment at 33 weeks gestation.
Transabdominal and transvaginal ultrasound demonstrate an abnormally low position of the placenta, covering the anterior lower uterine segment, and also the internal cervical os, in keeping with a major grade placenta praevia.
Multiple blood filled spaces are noted throughout the placenta (placental lacunae), a finding associated with abnormal placental adherence.
There is marked thinning of the anterior myometrium, with no appreciable myometrial tissue demonstrated between the placenta and the bladder serosa.
Colour imaging further supports the diagnosis, with marked placental vascularity and increased vascularity of the uterine-bladder interface
Case Discussion
Abnormal placental adherence is an important cause of maternal peripartum morbidity and mortality due to massive haemorrhage.
Awareness of the sonographic findings and vigilant imaging of patients with risk factors - in particular placenta praevia and multiple previous Caesarian sections - increases the likelihood of accurate prenatal diagnosis.
This in turn enables adequate pre-operative preparation, such as planned delivery at a tertiary institution, and preparation of a large quantity of crossmatched red blood cells.