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Screening for Trisomy 21 in Denmark; Evaluation of the Current and Possible Future Strategies

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Screening for Trisomy 21 in Denmark; Evaluation of the Current and Possible Future Strategies Faculty of Health Sciences University of Copenhagen Screening for trisomy 21 in Denmark; Evaluation of the current and possible future strategies PhD thesis Charlotte Kvist Ekelund Academic supervisors Ann Tabor, professor, DMSc, Department of Fetal Medicine, Rigshospitalet, University of Copenhagen Olav Bjørn Petersen, PhD, consultant, Department of Obstetrics, Aarhus University Hospital Ida Vogel, DMSc, Head of Department of Clinical Genetics, Aarhus University Hospital Evaluation committee Katja Bilardo, Professor, Head Fetal Medicine Unit, Department of Obstetrics & Gynaecology, University Medical Center Groningen, The Netherlands Michael Christiansen, Head of Molecular Diagnostics, Statens Serum Institute, Copenhagen Lone Krebs, DMSc, Associate professor, consultant, Department of Gynecology and Obstetrics, Holbæk Sygehus, University of Copenhagen The PhD defence will take place Friday the 13th of April 2012, Auditorium B, Teilum, Rigshospitalet, Copenhagen. Acknowledgement This thesis was made possible by help from a number of fantastic supervisors and colleagues. First and foremost, I owe my deepest thanks to Professor Ann Tabor. Thank you for sharing your interest and knowledge in first trimester screening with me, for your professional and personal guidance, for always having time and for showing your confidence in me from the very beginning of the project. Your constructive and focused attitude is admirable and to me you have been an extremely inspiring mentor within all aspects of life. I am greatly indebted to Olav Bjørn Petersen, MD, PhD, one of the most enthusiastic and optimistic persons I know. Your positive attitude, support and encouragement have really helped me through the challenging phases of the project. And my sincere thanks to Ida Vogel, MD, DMSc for taking part in the project, for everything you taught me many years ago and for still being there. I also want to thank my many co-authors for their contribution and cooperation. I have appreciated meetings and email correspondence with you all, and your help in collecting data and preparing manuscripts has been extremely valuable. Thanks to all departments which have contributed with important data for the national studies, and to the Fetal Medicine Departments at Hvidovre Hospital and Aarhus University Hospital for recruiting patients for the projects. At Rigshospitalet I would like to thank all my great and hardworking colleagues (secretaries, nurses, midwifes and doctors) at the Fetal Medicine Department for all your extraordinary help in recruiting and scanning the pregnant women, for giving me reasons to escape from the computer and for all your time invested in teaching me how to scan. I have had the privilege and pleasure to meet and work with the most inspiring international experts within the field of first trimester screening; Professor Jon Hyett, Royal Prince Alfred Hospital, University of Sydney and Professor Dave Wright and his group, University of Plymouth. Thank you for your sharing of knowledge, statistical help and hospitality. I am most grateful to Jan Hansen (Danish Cytogenetic Registry) and Steen Rasmussen (National Board of Health) who have both contributed significantly with national outcome data. Your always flexible support has been very much appreciated. I want to thank all my fantastic friends from the PhD office at Rigshospitalet for being an important and highly valuable part of my life for 4 years. It has been a true pleasure and comfort to share laughter and tears, victories and defeats with you. Finally, I want to thank my family and friends for their interest and support. And to Kim, Clara and Sofie: I love you so much. Charlotte Kvist Ekelund Copenhagen , March 2012 Content Preface and aims...................................................................................................................................... 3 List of abbreviations ................................................................................................................................. 4 Introduction ............................................................................................................................................ 5 Background ............................................................................................................................................. 6 Prenatal diagnosis and screening for chromosomal abnormalities ................................................................ 6 Prenatal diagnostic tests ............................................................................................................................. 6 Prenatal screening tests .............................................................................................................................. 7 Prenatal screening tests for trisomy 21..................................................................................................... 10 National guideline on prenatal screening ................................................................................................. 12 First trimester combined screening for trisomy 21 ....................................................................................... 14 Nuchal translucency .................................................................................................................................. 14 Biochemical markers ................................................................................................................................. 17 Combined first trimester screening performance ..................................................................................... 19 Alternative screening models .................................................................................................................... 22 Screening for other trisomies .................................................................................................................... 23 Quality control ........................................................................................................................................... 24 New biochemical markers ......................................................................................................................... 25 New ultrasound markers ........................................................................................................................... 26 Other advantages of first trimester screening .............................................................................................. 29 Ethical aspects, women’s attitude and choice .............................................................................................. 31 Epidemiological research in Fetal Medicine .................................................................................................. 33 Own studies ........................................................................................................................................... 35 Paper 1 ....................................................................................................................................................... 35 Paper 2 ....................................................................................................................................................... 37 Paper 3 ....................................................................................................................................................... 39 Paper 4 ....................................................................................................................................................... 41 Conclusion and future perspectives ........................................................................................................ 43 Summary in English ................................................................................................................................ 45 Dansk resume ........................................................................................................................................ 47 References ............................................................................................................................................. 49 Appendices (paper 1-4) .......................................................................................................................... 67 1 2 Preface and aims The present Ph.D. thesis is based on work carried out during my employment as a research fellow at the Department of Fetal Medicine, Rigshospitalet, Copenhagen University Hospital, Denmark during the period 2007-2011. The work was primarily supervised by professor, DMsc Ann Tabor, Department of Fetal Medicine, Rigshospitalet, Copenhagen. Head of Fetal Medicine Unit, Ph.D. Olav Bjørn Petersen and Head of Department of Clinical Genetics, DMSc Ida Vogel, Aarhus University Hospital have in addition contributed to the scientific plan and collection of data. The Ph.D. thesis is based on the following original papers I. Impact of a new national screening policy for Down's syndrome in Denmark: population based cohort study. Ekelund CK, Jorgensen FS, Petersen OB, Sundberg K, Tabor A, BMJ 2008; 337:a2547 II. First trimester screening for Trisomy 21 in Denmark: Implications on detection and birth rates of Trisomy 18 and Trisomy 13 . Ekelund CK, Petersen OB, Skibsted L, Kjaergaard S, Vogel I, Tabor A. Ultrasound Obstet Gynecol 2011;38(2):140-4 III. A prospective study evaluating the performance of first trimester combined screening for trisomy 21 using
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