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The CROWN Initiative: journal editors invite researchers to develop core outcomes in women’s health

Clinical trials, systematic reviews and guidelines compare beneficial and non-beneficial outcomes following interventions. Often, however, various studies on a particular topic do not address the same outcomes, making it difficult to draw clinically useful conclusions when a group of studies is looked at as a whole [1]. This problem was recently thrown into sharp focus by a systematic review of interventions for preterm birth prevention, which found that among 103 randomised trials, no fewer than 72 different outcomes were reported [2]. There is a growing recognition among clinical researchers that this variability undermines consistent synthesis of the evidence, and that what is needed is an agreed standardised collection of outcomes – a “core outcomes set” – for all trials in a specific clinical area [1]. Recognising that the current inconsistency is a serious hindrance to progress in our specialty, the editors of over 50 journals related to women’s health have come together to support The CROWN (CoRe Outcomes in WomeN’s health) Initiative (Table 1).

Table 1 Aims of the CROWN initiative

Development of consensus is required around a set of well-defined, relevant and feasible outcomes for all trials concerning particular obstetric and gynaecologic health conditions, such as preterm birth, incontinence, infertility and menstrual problems. With so many subspecialties involved, this is no easy task. Duplication of effort can be avoided by working with the Core Outcome Measures in Effectiveness Trials (COMET) Initiative, which is working towards core data sets for all medical specialties [3]. Production of trustworthy core outcome sets will require engagement with patients, healthcare professionals, researchers, industry and regulators, and the employment of scientifically robust consensus methods [1]. The data for these core outcome sets, once agreed upon, should be collected in trials and reported in publications as standard practice in the future.

Journal editors now invite researchers to take the lead in beginning this work. What will we do as editors to support them and their colleagues? First, we are drawing wide attention to The CROWN Initiative by publishing this editorial in the journals listed below. We shall ensure that the global research community, which includes our many reviewers, is aware of the need for core outcome sets. Submissions which describe development of core outcome sets, if deemed acceptable after peer review, will be effectively disseminated.

Our collaboration is not for enforcing harmony at the expense of innovation. To quote from the COMET home page ( “The existence or use of a core outcome set does not imply that outcomes in a particular trial should be restricted to those in the relevant core outcome set. Rather, there is an expectation that the core outcomes will be collected and reported, making it easier for the results of trials to be compared, contrasted and combined as appropriate; while researchers continue to explore other outcomes as well.” We also expect that as new or superior ways of capturing outcomes emerge, core outcome sets will themselves need updating.

Producing, disseminating and implementing core outcome sets will ensure that critical and important outcomes with good measurement properties are incorporated and reported. We believe this is the next important step in advancing the usefulness of research, in informing readers, including guideline and policy developers, who are involved in decision-making, and in improving evidence-based practice.


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  3. Williamson PR, Altman DG, Blazeby JM, Clarke M, Gargon E. The COMET (Core Outcome Measures in Effectiveness Trials) Initiative. Trials. 2011;12 Suppl 1:A70.

    Article  PubMed Central  Google Scholar 

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The CROWN Initiative is grateful to James Duffy (Trainee Scientific Editor, BJOG) and Louisa Waite (Assistant Editor, BJOG) for the drafting, revision and coordination required for the preparation of this article.

The CROWN Initiative includes the following journals, in alphabetical order (correct on 14th June 2016, up to date list available at

1. Acta Obstetricia et Gynecologica Scandinavica

2. American Journal of Obstetrics & Gynecology

3. American Journal of Perinatology

4. Archives of Gynecology and Obstetrics

5. Australian and New Zealand Journal of Obstetrics and Gynaecology

6. Best Practice & Research: Clinical Obstetrics & Gynaecology

7. Birth: Issues in Perinatal Care

8. BJOG: An International Journal of Obstetrics and Gynaecology

9. BMC Pregnancy and Childbirth

10. BMC Women's Health

11. Climacteric

12. Clinical Obstetrics and Gynecology

13. Clinics in Perinatology

14. Cochrane Menstrual Disorders and Subfertility Group

15. Cochrane Fertility Regulation Group

16. Cochrane Pregnancy and Childbirth Group

17. Contraception

18. Contraception & Reproductive Medicine

19. Current Opinion in Obstetrics and Gynecology

20. European Journal of Obstetrics & Gynecology and Reproductive Biology

21. Fertility and Sterility

22. Fertility Research and Practice

23. Female Pelvic Medicine and Reconstructive Surgery

24. Fetal Diagnosis and Therapy

25. Geburtshilfe & Frauenhelikunde

26. Ginekologia Polska

27. Gynecological Surgery

28. Gynecologic and Obstetric Investigation

29. Gynecologic Oncology

30. Gynecologic Oncology Reports

31. Human Fertility

32. Human Reproduction

33. Human Reproduction Update

34. Hypertension in Pregnancy

35. International Journal of Childbirth

36. International Journal of Fertility and Sterility

37. International Breastfeeding Journal

38. International Journal of Gynecological Cancer

39. International Journal of Gynecology & Obstetrics

40. International Urogynecology Journal

41. Journal de Gynecologie Obstétrique et Biologie de la Reproduction

42. Journal of Family Planning and Reproductive Health Care

43. Journal of Gynecologic Oncology

44. Journal of Lower Genital Tract Disease

45. Journal of Maternal Fetal and Neonatal Medicine

46. Journal of Midwifery & Women's Health

47. Journal of Minimally Invasive Gynecology

48. Journal of Obstetrics & Gynaecology

49. Journal of Obstetrics and Gynaecology Canada

50. Journal of Obstetrics and Gynecology Research

51. Journal of Obstetric, Gynecologic & Neonatal Nursing

52. Journal of Ovarian Research

53. Journal of Pediatric & Adolescent Gynecology (JPAG)

54. Journal of Perinatal & Neonatal Nursing

55. Journal of Perinatal Medicine

56. Maternal and Child Nutrition

57. Maternal Health, Neonatology and Perinatology

58. Maturitas

59. Midwifery

60. MCN The American Journal of Maternal Child Nursing

61. Menopause Review (Przegląd Menopauzalny)

62. Menopause: The Journal of The North American Menopause Society

63. Neurourology and Urodynamics

64. Nederlands Tijdschrift voor Obstetrie en Gynaecologie (NTOG)

65. New Zealand College of Midwives (NZCOM) Journal

66. Obstetrics & Gynecology

67. Paediatric and Perinatal Epidemiology

68. Placenta

69. Post Reproductive Health

70. Prenatal Diagnosis

71. Reproductive Health

72. Reproductive Health Library

73. Russian Journal of Obstetrics and Gynaecology

74. The Breast Journal

75. The European Journal of Contraception and Reproductive Health Care

76. The Obstetrician & Gynaecologist (TOG)

77. Twin Research and Human Genetics

78. Ultrasound in Obstetrics & Gynecology

79. Women and Birth

80. Women’s Midlife Health

81. Current Obstetrics & Gynecology Reports

Competing interests

The authors declare that they have no competing interest.


Reproduced from The Core Outcomes in Women’s Health (CROWN) Initiative with permission from the Royal College of Obstetricians and Gynaecologists and John Wiley & Sons Ltd.

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Correspondence to Khalid Khan.

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Khan, K., On behalf of Chief Editors of Journals participating in The CROWN Initiative listed at the end of this article. The CROWN Initiative: journal editors invite researchers to develop core outcomes in women’s health. Contracept Reprod Med 1, 16 (2016).

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  • Research design/standards
  • Treatment outcome
  • Endpoint determination/standards
  • Clinical trials
  • Systematic reviews
  • Guidelines
  • Bias (Epidemiology)
  • Evidence-based medicine
  • Consensus