title: Duration of Second Stage of Labour at Term and Pushing Time: Risk Factors for Postpartum Haemorrhage.
abstract: Prolonged labour is associated with increased risk of postpartum haemorrhage (PPH), but the role of active pushing time and the relation with management during labour remains poorly understood.
  
  
  
  A population-based cohort study from electronic medical record data in the Stockholm-Gotland Region, Sweden. We included 57 267 primiparous women with singleton, term gestation, livebirths delivered vaginally in cephalic presentation in 2008-14. We performed multivariable Poisson regression to estimate the association between length of second stage, pushing time, and PPH (estimated blood loss >500 mL during delivery), adjusting for maternal, delivery, and fetal characteristics as potential confounders.
  
  
  
  The incidence of PPH was 28.9%. The risk of PPH increased with each passing hour of second stage: compared with a second stage <1 h, the adjusted relative risk (RR) for PPH were for 1 to <2 h 1.10 (95% confidence interval (CI) 1.07, 1.14); for 2 to <3 h 1.15 (95% CI 1.10, 1.20); for 3 to <4 h 1.28 (95% CI 1.22, 1.33); and for ≥4 h 1.40 (95% CI 1.33, 1.46). PPH also increased with pushing time exceeding 30 min. Compared to pushing time between 15 and 29 min, the RR for PPH were for <15 min 0.98 (95% CI 0.94, 1.03); for 30-44 min 1.08 (95% CI 1.04, 1.12); for 45-59 min 1.11 (95% CI 1.06, 1.16); and for ≥60 min 1.20 (95% CI 1.15, 1.25).
  
  
  
  Increased length of second stage and pushing time during labour are both associated with increased risk of PPH.
authors.affiliation: Clinical Epidemiology Unit, Department of Medicine, Solna, Karolinska University Hospital and Institutet, Stockholm, Sweden.
authors.forename: Emelie
authors.initials: E
authors.lastname: Looft
authors.affiliation: Clinical Epidemiology Unit, Department of Medicine, Solna, Karolinska University Hospital and Institutet, Stockholm, Sweden.
authors.forename: Marija
authors.initials: M
authors.lastname: Simic
authors.affiliation: Clinical Epidemiology Unit, Department of Medicine, Solna, Karolinska University Hospital and Institutet, Stockholm, Sweden.
authors.forename: Mia
authors.initials: M
authors.lastname: Ahlberg
authors.affiliation: Departments of Obstetrics and Gynecology and Public Health and Preventive Medicine, Oregon Health and Science University, Portland, OR.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Snowden
authors.affiliation: Department of Surgery, University of California at Davis, Sacramento, CA.|Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, California Pacific Medical Center, San Francisco, CA.
authors.forename: Yvonne W
authors.initials: YW
authors.lastname: Cheng
authors.affiliation: Clinical Epidemiology Unit, Department of Medicine, Solna, Karolinska University Hospital and Institutet, Stockholm, Sweden.|Division of Epidemiology and Biostatistics, School of Public Health, University of California, Berkeley, CA.
authors.forename: Olof
authors.identifier: 0000-0003-1528-4563
authors.initials: O
authors.lastname: Stephansson
mesh_terms: D000328:Adult; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007748:Labor Stage, Second / Q000502:physiology; D007744:Obstetric Labor Complications / Q000453:epidemiology*; D036801:Parturition / Q000502:physiology; D006473:Postpartum Hemorrhage / Q000453:epidemiology / Q000209:etiology*; D011247:Pregnancy; D012307:Risk Factors; D013548:Sweden / Q000453:epidemiology; D055815:Young Adult
keywords: labour; postpartum haemorrhage; prospective cohort study; pushing; second stage