Obstetric outcomes in major vs minor placenta praevia: A retrospective cohort study

Placenta praevia (PP) is a rare obstetric condition associated with significant maternal and perinatal morbidity. Traditionally, the degree of PP has been classified into minor and major; however, there are very few robust studies that compare the maternal outcomes of these types of PP.

To identify any significant differences in obstetric outcomes between major and minor PP, including antepartum, intraoperative and postpartum complications.

A retrospective cohort study was conducted at the Royal Brisbane & Women's Hospital between 2009 and 2018; all women were diagnosed with PP.

Of the total of 368 women recruited, over half of the participants were diagnosed with major PP (57%), while the remaining had minor PP. Women with major PP, compared to women with minor PP, had an increased risk of antepartum haemorrhage (odds ratio (OR) 2.77, P < 0.001), delivery at an earlier gestational age (36.1 vs 37.4 weeks), general anaesthesia (OR 3.25, P < 0.001), greater proportion of emergency lower segment (51% vs 40%) and classical caesarean (7.7% vs 3.8%), increased number of uterotonics (incidence rate ratio (IRR) 1.17, P < 0.031), greater blood loss (IRR 1.32, P < 0.001) and higher frequency of blood transfusion (IRR 2.00, P < 0.027), and longer postpartum hospital stay (IRR 1.26, P < 0.001). Hysterectomy was performed for three women with major PP, compared to one with minor PP.

The degree of PP significantly impacts obstetric outcomes, with major PP associated with worse maternal morbidity antenatally, intraoperatively and postpartum. Therefore, to optimise patient care, this study emphasises the importance of identifying and distinguishing between different types of PP.