(121) Risk factors of severe postpartum hemorrhage in women with prior cesareans and abnormal placental location

Of the 520,114 women of the source population, 318 (0.61‰; 95% CI 0.55-0.68) had the combination of any prior cesareans and abnormal placental location and no suspicion of PAS before birth. After exclusion of women with missing data for the precise placental location (n=20) the study population included 298 women. The rate of severe PPH was 23.5% (70/298) (95% CI 18.8-28.7). Twenty-nine (9.7% (95% CI 6.6-13.7)) had a PAS diagnosed at birth. In the multivariate analysis, the factor associated with a significantly higher risk of severe PPH was the previa location of the placenta (compared with low lying or upper portion of the anterior lower uterine segment) (aOR: 2.59 95% CI 1.24-5.89).

Conclusion: PPH is frequent among women with any prior cesareans and abnormal placental location, even after exclusion of all women with PAS. The risk of PPH doubles when the placenta is previa versus no previa abnormal location. This knowledge provides scientific evidence to support guidelines and help to stratify the risk of severe PPH in these women.