Opium use during pregnancy and risk of preterm delivery: A population-based cohort study

• Siavash Maghsoudlou ,

  * E-mail: Siavash.Maghsoudlou@ki.se

  Affiliation Clinical Epidemiology Unit, Department of Medicine, Karolinska Institute, Solna, Sweden

  http://orcid.org/0000-0002-7721-9583

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• Sven Cnattingius,

  Affiliation Clinical Epidemiology Unit, Department of Medicine, Karolinska Institute, Solna, Sweden

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• Scott Montgomery,

  Affiliations Clinical Epidemiology Unit, Department of Medicine, Karolinska Institute, Solna, Sweden, Clinical Epidemiology and Biostatistics, School of Medical Sciences, Örebro University, Örebro, Sweden, Department of Epidemiology and Public Health, University College London, United Kingdom

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• Mohsen Aarabi,

  Affiliation Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran

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• Shahriar Semnani,

  Affiliation Faculty of Medicine, Golestan University of Medical Sciences, Gorgan, Iran

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• Anna-Karin Wikström,

  Affiliations Clinical Epidemiology Unit, Department of Medicine, Karolinska Institute, Solna, Sweden, Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden

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• Shahram Bahmanyar

  Affiliation Clinical Epidemiology Unit & Centre for Pharmacoepidemiology, Department of Medicine, Karolinska Institute, Solna, Sweden

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