The risk of adverse maternal outcomes in cases of placenta praevia in an Australian population between 2007 and 2017.

Abstract

Placenta praevia is characterised by an inferior placental margin that overlies or falls within 20mm of the endocervical os. It remains a common cause of antepartum haemorrhage and is associated with adverse maternal and neonatal outcomes. We aimed to determine the association between antepartum and postpartum haemorrhage and adverse outcomes in cases of placenta praevia. The study population included women diagnosed with placenta praevia, who delivered between 1 April 2007 and 30 April 2017. The endpoints of interest included blood transfusion, emergency caesarean section, peripartum hysterectomy and admission to intensive care. There were 513 cases of placenta praevia, of which 67.3% delivered at term. Antepartum haemorrhage was associated with an increased risk of blood transfusion (relative risk (RR) 3.29; 95% CI 2.04-5.32), emergency caesarean section (RR 1.38; 95% CI 1.18-1.62) and preterm delivery, after 32weeks gestation (RR 4.21; 95% CI 2.77-6.38). Postpartum haemorrhage more than doubled the risk of blood transfusion (RR 9.08 95% CI 5-16.44) and admission to the intensive care unit (RR 10.44; 95% CI 2.34-46.59), as well as increased the risk of peripartum hysterectomy (1.4%). We also described the management of 12 cases of placenta praevia (2.3% of the study population) delivered vaginally. Antepartum and postpartum haemorrhage in cases of placenta praevia are predictors of several adverse outcomes. However, the high rate of term deliveries reaffirms the current practice of expectant management.