EP16.32: Determinants of emergency delivery in pregnancies complicated by placenta accreta spectrum or placenta previa: multicentre study

To report rate and outcomes of emergency Caesarean delivery (CD) delivery in women with placenta accreta spectrum (PAS) and placenta previa without PAS, and the diagnostic accuracy of ultrasound in predicting this outcome. Secondary analysis of a prospective study involving 14 referral hospital in Italy (ADoPAD Study). Inclusion criteria were women with a low-lying placenta or placenta previa undergoing TA and TV ultrasound assessment at ≥ 26 weeks. Primary outcome was the occurrence of emergency CD for either maternal or fetal indications in women with PAS and in those with placenta previa with no PAS. Univariate, multivariate, and diagnostic accuracy analyses were performed. 450 women (97 with PAS and 353 with placenta previa but not PAS) were included. In women with PAS, emergency CD occurred in 21% and 60% delivered before 34 weeks. Compared with elective CD, emergency CD was associated with lower GA at delivery (32.3 ± 2.7 vs 34.9 ± 1.8 weeks; p < 0.001), higher median estimated blood loss (2500ml, IQR 1350-4500 vs 1100ml, IQR 625-2500, p = 0.012) and mean units of blood transfused (4.3 ± 1.6 vs 0.8 ± 2.2; p= 0.02). At univariate analysis, the presence of interrupted retroplacental space, bladder line and placental lacunae were more common but not predictive of emergency CD. At multivariate analysis, only maternal BMI was significantly associated with emergency CD. In women with placenta previa but not PAS, emergency CD occurred in 31.1% and 32.8% delivered before 34 weeks. Emergency CD was associated with lower GA at delivery (34.2 ± 2.9 vs 36.7 ± 1.6 weeks; p < 0.001), lower birthweight (2330 ± 620g vs 2800 ± 620g, p < 0.001) and higher risk of receiving blood transfusions (22.7% vs 10.7%, p= 0.003). At multivariate analysis, only placental thickness and cervical length < 25mm were associated with emergency CD, with the latter showing low diagnostic accuracy for predicting emergency CD. Emergency CD complicated about 20% of PAS and 30% of placenta previa but not PAS and ultrasound cannot entirely predict the risk of emergency CD in women with these disorders.