Hemorrhage After Manual Removal of the Placenta: Weighing Risk Factors and the Role of the Third Stage of Labor
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CitationPerlman, Nicola. 2018. Hemorrhage After Manual Removal of the Placenta: Weighing Risk Factors and the Role of the Third Stage of Labor. Doctoral dissertation, Harvard Medical School.
AbstractIntroduction: Manual removal of the placenta, often due to uterine atony or an abnormally adherent placenta, can be accompanied by severe maternal postpartum hemorrhage. The objective of this study was to identify risk factors for postpartum hemorrhage that would allow triaging of most morbid patients prior to manual removal.
Methods: This was a retrospective case control study of patients who had undergone manual removal of the placenta after vaginal delivery at Brigham and Women’s Hospital between January 1, 2007 and May 29, 2015. We evaluated risk factors for postpartum hemorrhage independently and by presumed causative role. Causative groups (and risk factors) included Atony (multiple gestation, prolonged second stage of labor, birth weight >4000g, parity>4, or BMI>40kg/m2), Abnormal Placentation (>2 prior D&Es, suspicion for accreta on ultrasound, ART, age>40 years, prior cesarean, prior accreta, prior retained placenta, prior uterine surgery, resolved low lying placenta, or Ashermans syndrome), or Other Postpartum Hemorrhage Risk Factors (preeclampsia, acute abruption, fibroids >6cm, or preterm delivery). Risk factors were also classified as either major (concern for accreta on ultrasound or signs of abruption at admission) or minor (any other variable), and we analyzed whether any one major or two minor risk factors, regardless of causative grouping, were associated with postpartum hemorrhage after manual removal. Length of third stage of labor was analyzed in relation to patient characteristics. All significant variables were put into a multivariable analysis to test for confounding.
Results: Of the 997 women identified with manual removal of the placenta during our study period, 172 experienced severe postpartum hemorrhage and were one-to-one matched with controls without hemorrhage. Case patients were more likely than controls to have any one risk factor in either the Atony (49% vs. 37% respectively , p = 0.01) or Abnormal Placentation risk group (58% vs. 38%, respectively, p<0.01) and additionally were more likely to have any one major or two minor risk factors (51% vs. 26% controls; p>0.01). Postpartum hemorrhage patients had manual removal of the placenta later in the third stage of labor (p<0.01). Characteristics associated with rapid manual removal of the placenta within 30 minutes after delivery of the infant included cord avulsion and epidural analgesia (p<0.01), whereas chorioamnionitis was associated with delay until manual removal (p=0.03). Increasing length of third stage of delivery showed strong association with postpartum hemorrhage in our multivariate analysis, along with risk factors for abnormal placentation. Though significant in the univariate analysis, chorioamnionitis, a risk factor for uterine atony, showed no association with postpartum hemorrhage after controlling for other factors in our multivariable regression.
Conclusion: Patients with concern for uterine atony should have rapid removal of the placenta, regardless of chorioamnionitis and epidural analgesia, in order to minimize risk of postpartum hemorrhage. Patients with risk factors for abnormal placentation or placenta accreta may not have risk of hemorrhage mitigated by rapid manual delivery.
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