Risk factors for postpartum hemorrhage in pregnancies complicated by polyhydramnios

To investigate the prevalence and the risk factors for postpartum hemorrhage (PPH) among pregnancies with polyhydramnios.

We conducted a retrospective single-center study, including all women who presented with polyhydramnios, defined clinically as ≥ 2 L or by ultrasound with an Amniotic Fluid Index >25 cm or a Deepest Vertical Pocket >8 cm, from 2015 to 2022 at the Department of Gynecology and Obstetrics of Rouen University Hospital. We excluded cases of multiple pregnancies and preterm deliveries before 32 weeks of gestation. Our study population was divided into two groups based on the occurrence of PPH, defined as genital blood loss ≥500 ml within the first 24 h following childbirth. Maternal, gestational, and delivery characteristics were compared using univariate analysis. To explore an independent association between the studied factors and the risk of PPH, we performed a logistic regression model.

In our source population including all women from 2015 to 2022, there was a significant difference in the rate of PPH, which was 8.0 % among women with polyhydramnios (n = 35/437) compared to 5.1 % without (n = 1107/21,633, p = 0.01). In our study population based on polyhydramnios, among the 387 women included after application of exclusion criteria, 31 (8 %) of them experienced PPH. We found a significantly higher rate of failure to perform prophylactic oxytocin administration in the PPH group (2.3 % vs. 9.7 %, p < 0.05). We found a higher rate of cesarean section in the PPH group VS no PPH (43.5 % vs. 61.3 %, p = 0.06) but not significantly. After adjustment, our study found cesarean section as an independent risk factor for PPH (OR = 2.5, [1.1 - 5.8]), while prophylactic oxytocin was an independent protective factor against PPH (OR = 0.1, [0.1 - 0.4]).

In cases of polyhydramnios, cesarean section and the absence of prophylactic oxytocin administration are risk factors for PPH.