Cesarean delivery and fetal macrosomia are significant independent risk factors for postpartum hemorrhage (PPH) in pregnancies with polyhydramnios, whereas the use of prophylactic oxytocin acts as a significant protective factor. These findings from a single-center study were published in the Journal of Gynecology Obstetrics and Human Reproduction.¹

Researchers from the Dept. of Obstetrics and Gynecology, Charles Nicolle University Hospital, Rouen, France conducted this study to determine the prevalence and risk factors for PPH in pregnancies complicated by polyhydramnios. Women with multiple pregnancies and preterm deliveries before 32 weeks of gestation were not included in the study. Polyhydramnios was defined as an amniotic fluid index >25 cm, or deepest vertical pocket >8 cm by ultrasound, or clinically as ≥2 L of fluid. PPH was  defined as genital blood loss ≥500 ml within the first 24 hours after delivery. The mean age of the participants was 31.8 years; the average BMI was 26.4 kg/m². Nearly one-quarter were primiparous and 5.7% had a prior history of PPH.

Retrospective analysis of data of all women between 2015 and 2022 revealed a PPH rate of 8% among women with polyhydramnios, higher than in pregnancies without polyhydramnios (5.1%). Among the study population of 387 women with polyhydramnios, 8% had experienced PPH. A significantly higher likelihood of missed prophylactic oxytocin administration was observed among women who experienced PPH compared to those who did not (9.7% vs 2.3%). Although a higher cesarean section rate was observed in the PPH group (43.5 % vs 61.3 %), the difference was not statistically significant (p = 0.06).

Cesarean section was found to be an independent risk factor for PPH with odds ratio (OR) of 2.5. Fetal macrosomia was also associated with an increased risk of PPH (OR 2.8). Prophylactic oxytocin administration, on the other hand, was found to be an independent protective factor (OR 0.1). The authors noted that “a history of PPH (OR = 3.1) tends also to be a risk factor for PPH, without significant results”.

According to the authors, this is the first study to identify the risk factors for PPH in cases of polyhydramnios. Enhanced monitoring in the post-interventional recovery room with assessments carried out at least every 30 minutes during the first two hours focusing on external genital bleeding, uterine size, and tone, facilitates timely detection and intervention if postpartum blood loss exceeds 500 mL. The study further suggests that clinicians adhere to prophylactic oxytocin guidelines and “consider initiating a slow intravenous oxytocin infusion in cases where cesarean section is necessary” to prevent PPH especially in pregnancies with polyhydramnios.

Reference

1.   Leclerc C, et al. Risk factors for postpartum hemorrhage in pregnancies complicated by polyhydramnios. J Gynecol Obstet Hum Reprod. 2025 Apr 19;54(6):102959. doi: 10.1016/j.jogoh.2025.102959.