Incidence and Risk Factors for Postpartum Hemorrhage: A Case-Control Study in a Tertiary Hospital in Greece

Background and Objectives: Postpartum hemorrhage (PPH) is an obstetrical emergency and although the mortality rate from PPH has decreased, it is still considered a challenge in obstetrics. This study aimed to estimate the rate of primary PPH, as well as to investigate the potential risk factors and management options. Material and methods: This was a retrospective case-control study of all cases with PPH (blood loss > 500 mL, irrespective of the mode of delivery) managed in the Third Department of Obstetrics and Gynecology, Aristotle University of Thessaloniki, Greece, from 2015 to 2021. The ratio of cases to controls was estimated to be 1:1. The chi-squared test was used to examine if there was any relationship between several variables and PPH, while subgroup multivariate logistic regression analyses of certain causes of PPH were also conducted. Results: During the study period, from a total of 8545 births, 219 (2.5%) pregnancies were complicated with PPH. A maternal age > 35 years (OR: 2.172; 95% CI: 1.206-3.912; p = 0.010), preterm delivery (<37 weeks) (OR: 5.090; 95% CI: 2.869-9.030; p < 0.001) and parity (OR: 1.701; 95% CI: 1.164-2.487; p = 0.006) were identified as risk factors for PPH. Uterine atony was the main cause of PPH in 54.8% of the women, followed by placental retention in 30.5% of the sample. Regarding management, 57.9% (n = 127) of the women received uterotonic medication, while in 7.3% (n = 16), a cesarean hysterectomy was performed to control PPH. Preterm delivery (OR: 2.162; 95% CI: 1.138-4.106; p = 0.019) and delivery via a cesarean section (OR: 4.279; 95% CI: 1.921-9.531; p < 0.001) were associated with a higher need for multiple treatment modalities. Prematurity (OR: 8.695; 95% CI: 2.324-32.527; p = 0.001) was identified as an independent predictor for an obstetric hysterectomy. From the retrospective analysis of the births complicated by PPH, no maternal death was identified. Conclusions: Most of the cases complicated with PPH were managed with uterotonic medication. An advanced maternal age, prematurity and multiparity had a significant impact on the occurrence of PPH. More research is needed on the risk factors of PPH, while the establishment of validated predictive models would be of value.