A comparison of praevia and non-praevia outcomes in placenta accreta spectrum cases: A single centre analysis

Placenta accreta spectrum (PAS) causes severe maternal morbidity and mortality. Antenatal diagnosis can optimise maternal outcomes and reduce the risk of complications. PAS cases where the placenta is not low lying are suggested to be more difficult to diagnose antenatally and are potentially associated with different outcomes.

The aim was to compare factors associated with births in PAS pregnancies with and without placenta praevia at a single tertiary centre over 15 years.

A retrospective review of all births complicated by PAS was conducted from a site-specific database. Cases with and without a placenta praevia were analysed to compare differences in maternal risk factors, outcomes and histological diagnosis.

Between June 2006 and July 2020 there were 134 cases of PAS, 106 with placenta praevia. Cases without praevia were less likely to have a history of previous caesarean section and to be admitted for delivery planning or with antepartum haemorrhage. A higher proportion of cases without praevia were delivered at term, with no overall difference in emergency or elective deliveries. There was a significantly lower rate of hysterectomy in the non-praevia group. The overall estimated blood loss was significantly lower in those without praevia.

Suspected PAS without placenta praevia is at lower risk of hysterectomy and massive blood loss. The management approach can be tailored accordingly, with good operative outcomes with transverse abdominal and uterine incisions. Antenatal diagnosis can be difficult to accurately predict the degree of invasion, and a higher level of suspicion is required.