Incidence, risk factors and perinatal outcomes for placenta accreta in Australia and New Zealand: A case-control study

© Article author(s) 2017. Objective Estimate the incidence of placenta accreta and describe risk factors, clinical practice and perinatal outcomes. Design Case-control study. Setting Sites in Australia and New Zealand with at least 50 births per year. Participants Cases were women giving birth (≥20 weeks or fetus ≥400 g) who were diagnosed with placenta accreta by antenatal imaging, at operation or by pathology specimens between 2010 and 2012. Controls were two births immediately prior to a case. A total of 295 cases were included and 570 controls. Methods Data were collected using the Australasian Maternity Outcomes Surveillance System. Primary and secondary outcome measures Incidence, risk factors (eg, prior caesarean section (CS), maternal age) and clinical outcomes of placenta accreta (eg CS, hysterectomy and death). Results The incidence of placenta accreta was 44.2/100 000 women giving birth (95% CI 39.4 to 49.5); however, this may overestimated due to the case definition used. In primiparous women, an increased odds of placenta accreta was observed in older women (adjusted OR (AOR) women≥40 vs