Duration of Expulsive Efforts and Risk of Postpartum Hemorrhage in Nulliparous Women: A Population-Based Study

Abstract

ObjectiveTo assess the specific association between the duration of expulsive efforts and the risk of postpartum hemorrhage.MethodsPopulation-based cohort-nested case-control study of nulliparous women delivering vaginally in 106 French maternity units between December 2004 and November 2006, including 3,852 women with PPH (blood loss ≥ 500 mL and/or peripartum Hb decrease ≥ 2 g/dL), 1,048 of them severe (peripartum Hb decrease ≥ 4 g/dL or transfusion of ≥ 2 units of red blood cells), and 762 controls from a representative sample of deliveries without hemorrhage in the same population. The association between duration of expulsive efforts and postpartum hemorrhage was estimated by multilevel logistic regression models adjusted for individual and hospital characteristics.ResultsMedian duration of expulsive efforts was 18 minutes among controls, 20 minutes among postpartum hemorrhage and 23 minutes among severe postpartum hemorrhage (p<0.01). Duration of expulsive efforts was significantly, positively, and linearly associated with both postpartum hemorrhage and severe postpartum hemorrhage. After adjustment for other risk factors, every additional 10 minutes of expulsive efforts was associated with about a 10% increase in the risk of postpartum hemorrhage (aOR = 1.11 [1.02–1.21]) and severe postpartum hemorrhage (aOR = 1.14 [1.03–1.27]). Oxytocin during labor, duration of active phase of labor, forceps use, episiotomy, perineal tears, and birth weight were also independently associated with both risks.ConclusionDuration of expulsive efforts was independently associated with postpartum hemorrhage and severe postpartum hemorrhage. Interventions to shorten the duration of this stage, such as oxytocin, forceps, and episiotomy, are also associated with higher risks of postpartum hemorrhage. Beyond duration, other aspects of the management of active second stage should be evaluated as some might allow it to last longer with a minimal increase in postpartum hemorrhage risk.

Duration of Second Stage of Labour at Term and Pushing Time: Risk Factors for Postpartum Haemorrhage

“…While numerous studies have examined the association between duration of second stage and associated maternal and neonatal outcomes, [9][10][11][12][13][14]16 few had PPH as a primary outcome. 15,17,23 As such, the effect estimate between duration of second stage and PPH can be prone to biases such as ascertainment, confounding, selection, or misclassification. As our findings are consistent with several previous studies, 9,10,12,24 this study was specifically designed to examine PPH as a primary outcome.…”

“…Our findings were consistent with one large randomised controlled trial of delayed vs. active pushing which reports an increased risk of PPH after 2 h of pushing, 16 and in line with a French study demonstrating a linear association between the expulsive phase duration and PPH risk. 17 Thus, prolonged pushing time, especially in women with a long second stage, warrants potential preventive actions for PPH, balancing the risks and benefit of instrumental and operative deliveries weighed against those of expectant management.…”

“…While numerous studies have examined the association between duration of second stage and associated maternal and neonatal outcomes, few had PPH as a primary outcome . As such, the effect estimate between duration of second stage and PPH can be prone to biases such as ascertainment, confounding, selection, or misclassification.…”

“…A US study also examined the role of pushing time and found increased risk of PPH after 2 h of pushing . In addition, a French study reported a linear increased risk of PPH with expulsion duration . However, many of these studies have limitations in study design and methodology .…”

“…16 In addition, a French study reported a linear increased risk of PPH with expulsion duration. 17 However, many of these studies have limitations in study design and methodology. 18 Some of these limitations include inconsistency in the definition of PPH, oversimplified categorisation of prolonged second stage of labour without consideration given specifically to pushing time, lack of control of maternal and delivery characteristics for the study population.…”