Postpartum hemorrhage: risk factors for severe blood loss, surgical intervention and peripartum hysterectomy.

Purpose: To evaluate risk factors in patients presenting with postpartum hemorrhage (PPH) associated with severe blood loss (BL), surgical intervention or peripartum hysterectomy.

Methods: This retrospective cohort study included all patients who gave birth at the Hannover Medical School between January 2013 and August 2022 with PPH, defined as BL ≥ 500 ml after vaginal delivery and ≥ 1000 ml after cesarean section. The threshold for severe PPH was set at BL ≥ 1500 ml. Operative management included manual placental removal and/or aspiration/curettage, need for intrauterine balloon tamponade, uterine packing with a chitosan covered gauze or compression sutures. Hysterectomy as ultima ratio was observed separately.

Results: In total 20.9% of 1038 patients with PPH developed severe BL. Several risk factors were identified such as nicotine abuse (aOR 3.45, 95% CI 1.57-7.59, p = 0.002), multiparity (aOR 2.12, 95% CI 1.10-4.10, p = 0.03), uterine malformation (aOR 5.09, 95% CI 1.22-21.16, p = 0.03), c-section (aOR 3.92, 95% CI 2.59-5.92, p < 0.001), placenta praevia (aOR 2.82, 95% CI 1.2-6.63, p = 0.02), abnormal placentation (aOR 9.76, 95% CI 4.22-22.56, p < 0.001) and inversion of the uterus (aOR 16.89, 95% CI 1.62-176.12, p = 0.02). More than one third of the women had a surgical intervention. Independent risk factors for an operative management of PPH were uterus malformation (aOR 5.04, 95% CI 1.22-20.91, p = 0.03), placenta praevia (aOR 2.84, 95% CI 1.23-6.53, p = 0.01), abnormal placentation (aOR 9.78, 95% CI 4.30-22.27, p < 0.001) and c-section (aOR 4.65, 95% CI 3.14-6.89, p < 0.001). Peripartum hysterectomy occurred in 1.9% of the cases and was in addition independently associated wih preeclampsia (aOR 7.50, 95% CI 1.29-43.81, p = 0.03) and amniotic infection syndrome (aOR 12.22, 95% CI 1.92-77.90, p = 0.01).

Conclusion: PPH is a common complication in modern obstetrics and one in five patients with pathological bleeding after birth develops severe BL. There are specific risk factors associated with a BL ≥ 1500 ml, surgical intervention and peripartum hysterectomy in PPH that should be assessed by health professionals and taken into account in the management of this postpartum complication.