Duration of labor and the risk of severe postpartum hemorrhage: A case-control study.

Lill Trine Nyfløt,Siri Vangen,Lisa Forsén,Babill Stray-Pedersen,Shannon M Hawkins

doi:10.1371/journal.pone.0175306

Lill Trine Nyfløt, Siri Vangen + Show 3 more

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https://doi.org/10.1371/journal.pone.0175306

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Abstract

ObjectiveOur main objective was to investigate the association between duration of active labor and severe postpartum hemorrhage. We examined the effect of the total duration of active labor, the effect of each stage of active labor, and the gradient effect of duration of labor on severe postpartum hemorrhage.MethodsA case-control study was generated from a source population of all women admitted for delivery at Oslo University Hospital and Drammen Hospital in Buskerud municipality during the time period January 1, 2008 to December 31, 2011. The study population included all cases of severe postpartum hemorrhage (n = 859) and a random sample of controls (n = 1755). Severe postpartum hemorrhage was defined as postpartum blood loss ≥1500 mL or need for blood transfusion. Prolonged labor was defined as duration of active labor >12 hours according to the definition of the World Health Organization. We used logistic multivariable regression in the analysis.ResultsWe observed a significantly longer mean duration of labor in women who experienced severe postpartum hemorrhage compared to controls (5.4 versus 3.8 hours, p<0.001). Women with severe postpartum hemorrhage also had a longer duration of all stages of active labor compared to controls. The association between the duration of active labor and severe postpartum changed from a linear dose-response association to a threshold association after adjusting for augmentation with oxytocin, induction of labor, primiparity, and fever during labor. Compared to controls, women with severe postpartum hemorrhage were more likely to have a prolonged labor >12 hours (adjusted odds ratio = 2.44, 95% confidence interval: 1.69–3.53, p< 0.001).ConclusionProlonged active labor (duration >12 hours) was associated with severe postpartum hemorrhage. Increased vigilance seems required when the labor is prolonged to reduce the risk of severe postpartum hemorrhage.

Highlights

Severe postpartum hemorrhage (PPH) contributes substantially to maternal morbidity in high-income countries, causing >50% of all severe maternal morbidity [1]
We observed a significantly longer mean duration of labor in women who experienced severe postpartum hemorrhage compared to controls (5.4 versus 3.8 hours, p
Women with severe postpartum hemorrhage had a longer duration of all stages of active labor compared to controls

Summary

Introduction

Severe postpartum hemorrhage (PPH) contributes substantially to maternal morbidity in high-income countries, causing >50% of all severe maternal morbidity [1]. Recent studies have shown an increasing trend in PPH, but the causes for this increase are still uncertain [2,3,4] Obstetric interventions such as inductions of labor and oxytocin during labor, are increasingly common and believed to influence both the duration of labor and the risk for severe PPH [5,6,7,8,9,10]. By comparing labor patterns in the 1960s with a modern cohort, a study by Laughon et al [11] found an increased duration of the first stage of labor They observed an increased use of obstetric interventions such as oxytocin, epidurals, and induction of labor in addition to the mothers being both older and of greater body mass index (BMI). The World Health Organization (WHO) defines a prolonged active phase as regular painful contractions for more than 12 hours after cervical dilation of !4 cm [13]

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