Retained placenta and postpartum hemorrhage

Objective:

Postpartum hemorrhage (PPH) is the major cause of maternal deaths worldwide and retained placenta – defined as a third stage exceeding 30 minutes – is responsible for 18% of all PPH cases. The aim of this study was to investigate the clinical course of women with retained placenta in a Swiss obstetrical cohort. Moreover, the influence of the time factor and the etiology of retained placenta on the dynamics of postpartum hemorrhage were analyzed.

Methods:

This retrospective monocentric cohort study investigated 296 women diagnosed with retained placenta after vaginal delivery at the University hospital Zurich. The third stage of labor was actively managed in all cases. Blood loss was estimated by weighing soaked drapes and using calibrated surgical drapes with a scaled blood-collecting pouch. PPH was defined as blood loss ≥500 ml in 24 hours. Antepartum and one day postpartum hemoglobin levels were measured to obtain postpartum drop of hemoglobin (g/l). Descriptive statistics and stratification by length of the third stage of labor (< 60 minutes, ≥60 minutes) as well as subgroup analysis of women with or without uterine atony was performed. A Spearman Rank correlation was conducted to analyze the association between the duration of the third stage of labor with blood loss parameters (estimated blood loss and postpartum drop of hemoglobin).

Results:

Postpartum hemorrhage was seen in 96.6% of all cases. The median blood loss was 1300 ml (IQR 900 – 1900 ml) and median drop of hemoglobin was 39 g/l (IQR 26 – 54 g/l). In patients with third stage of labor < 60 minutes, uterine atony (p = 0.001), blood transfusion (p = 0.006) and multiple pregnancies (p = 0.03) were significantly more common. In women with uterine atony (27.4%), a significantly larger drop of hemoglobin (55 g/l vs. 35 g/l, p < 0.001), higher blood loss (2000 ml vs. 1100 ml, p < 0.001), more cases of PPH (100% vs. 95.4%, p = 0.048), higher risk of blood transfusion (13.6% vs. 0.9%, p = 0.002), general anesthesia (32% vs. 20%, p < 0.001) and admission to the ICU postpartum (6.2% vs. 0.5%, p = 0.002) was detected. Overall, we did not find a gradual increase in blood loss or drop in hemoglobin levels over time in the third stage of labor.

Conclusion:

Our data suggests that there is neither a safe time window in the management of retained placenta nor a clinically reasonable cutoff point, when a manual removal of the placenta has to be performed. In fact, increased blood loss depends on the etiology of the retained placenta and is not associated with the duration of the third stage of labor. Uterine atony leading to retained placenta causes heavy postpartum hemorrhage immediately after delivery, therefore early detection is required followed by instant manual removal of the placenta.