RISK FACTORS FOR EMERGENT DELIVERY BEFORE 36 WEEKS AMONG PREGNANT WOMEN WITH PLACENTA ACCRETA SPECTRUM DISORDER – EXPERIENCE FROM A TERTIARY CENTER IN THAILAND

Problem statement: Prenatal diagnosis of placenta accreta spectrum (PAS) followed by early, planned delivery by an experienced team can improve maternal outcomes at the expense of iatrogenic prematurity. Currently, there is inadequate high-quality evidence regarding delivery timing for women with PAS. Most studies on this topic have small sample sizes, and some reported a mixed population with PAS and placenta previa. Our study was conducted to evaluate the risk factors for emergent delivery before gestational age (GA) 36 weeks in women with PAS disorders.
Methods: A retrospective case-control study was conducted at a tertiary-level hospital in Southern Thailand. Women with prenatal suspicion of PAS who delivered between January 2007 and December 2022 were included. Women who delivered before GA 36 weeks electively or for conditions unrelated to PAS were excluded. Women who had emergent delivery before 36 weeks and who delivered after 36 weeks were compared using univariate and multivariate analysis. Statistical significance was set at P<0.05.

Results: 177 women with PAS were included in the study; 48 (27.1%) underwent emergent delivery before 36 weeks. Women who had emergent delivery before 36 weeks were more likely to have premature uterine contractions (PUC) before 34 weeks (41.7% vs. 7.0%, p<0.001), premature rupture of membranes before 34 weeks (8.3% vs. 0%, p=0.005), and antepartum hemorrhage (APH) before 34 weeks (75.0% vs 27.9%, p<0.001), compared to women who delivered after 36 weeks. The number of PUC and APH episodes also correlates with an increased risk of emergent delivery (p<0.001). A higher degree of PAS was also significantly associated with emergent delivery (p=0.003). Multivariate logistic regression analysis shows that factors significantly predictive of emergent delivery before 36 weeks are the presence of PUC (OR 4.1, 95%CI 1.5-11.5) and APH (OR 5.7, 95%CI 2.2-14.6).

Conclusion: Factors associated with emergent delivery before GA 36 weeks were PUC and APH before 34 weeks. Our finding suggests that the timing of delivery in women with PAS should be individualized based on maternal risk factors for the best outcomes for both the pregnant women and the newborns.