title: Maintaining factors of posttraumatic stress symptoms following childbirth: A population-based, two-year follow-up study.
abstract: BACKGROUND
  Previous research has established a number of risk factors that are associated with the onset of PTSD following childbirth. However, little is known about factors that maintain PTSD symptoms.
  
  
  METHODS
  This study is part of the Akershus Birth Cohort. Questionnaire data from pregnancy week 17, 8 weeks postpartum and 2 years postpartum were used. 1473 women completed all these three questionnaires and were included in the analyses. Post-traumatic stress symptoms were measured with the Impact of Event Scale. Potential maintaining factors were personality, sleep, support and life events. The factors that were significantly correlated with post-traumatic stress symptoms were entered into regression analyses. Mediation analyses were run to test whether significant predictors would serve as mediator of post-traumatic stress symptoms at 8 weeks postpartum to post-traumatic stress symptoms at 2 years postpartum.
  
  
  RESULTS
  We found several low to moderate associations between maintaining factors and PTSD symptoms two years postpartum. Adjusting for the starting point - PTSD symptoms 8 weeks postpartum - only insomnia remained significantly associated. Further, insomnia mediated a small portion of the effect of PTSD symptoms 8 weeks postpartum to PTSD symptoms 2 years postpartum.
  
  
  CONCLUSIONS
  Limitations of the study include a relative homogeneous sample, modest effect sizes, low internal consistency of some of the measures and the challenge to distinguish insomnia from PTSD symptoms.
  
  
  CONCLUSIONS
  Treatment of postpartum PTSD might benefit from addressing insomnia if present. Alleviating insomnia may itself reduce daytime symptoms of PTSD and it may also increase the efficacy of primary PTSD treatments.
authors.affiliation: Institute and Policlinic of Occupational and Social Medicine, TU Dresden, Faculty of Medicine, Fetscherstr. 74, 01307 Dresden, Germany; Department of Psychosomatics and Health Behavior, Norwegian Institute of Public Health, Oslo, Norway. Electronic address: susan.garthus-niegel@tu-dresden.de.
authors.forename: Susan
authors.initials: S
authors.lastname: Garthus-Niegel
authors.affiliation: Centre for Maternal and Child Health, School of Health Sciences, City University London, London, UK.
authors.forename: Susan
authors.initials: S
authors.lastname: Ayers
authors.affiliation: Department of Childhood, Development, and Cultural Diversity, Norwegian Institute of Public Health, Oslo, Norway; Department of Psychology, University of Oslo, Norway.
authors.forename: Tilmann
authors.initials: T
authors.lastname: von Soest
authors.affiliation: Department of Psychosomatics and Health Behavior, Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: Leila
authors.initials: L
authors.lastname: Torgersen
authors.affiliation: Department of Psychosomatics and Health Behavior, Norwegian Institute of Public Health, Oslo, Norway; HØKH, Research Centre, Akershus University Hospital, Norway.
authors.forename: Malin
authors.initials: M
authors.lastname: Eberhard-Gran
mesh_terms: D000328:Adult; D003220:Conflict, Psychological; D015986:Confounding Factors, Epidemiologic; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007398:Interpersonal Relations; D008016:Life Change Events; D036801:Parturition / Q000523:psychology*; D010551:Personality; D049590:Postpartum Period; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D012307:Risk Factors; D057566:Self Report; D012890:Sleep; D007319:Sleep Initiation and Maintenance Disorders / Q000523:psychology; D013313:Stress Disorders, Post-Traumatic / Q000209:etiology*
keywords: Akershus Birth Cohort; Maintaining factors; Posttraumatic stress symptoms following childbirth