title: Thyroid function and autoimmunity in Danish pregnant women after an iodine fortification program and associations with obstetric outcomes.
abstract: OBJECTIVE
  Aberrations in maternal thyroid function and autoimmunity during pregnancy have been associated with negative obstetric outcome. In Denmark, a national iodine fortification program was implemented in the year 2000 with the aim to alleviate the mild-moderate iodine deficiency. Following the iodine implementation, there has been an increase in thyroid autoimmunity in the background population. This study investigates the thyroid status of pregnant Danish women following the iodine fortification program, and a possible association with preterm delivery.
  
  
  METHODS
  Historical cohort study of 1278 randomly selected pregnant Danish women attending the national Down's syndrome screening program.
  
  
  METHODS
  The main outcome measures were thyroid status according to laboratory- and gestational-age-specific reference intervals, and association with risk of abnormal obstetric outcome. Antibody-positivity was defined as an antibody-level (thyroid peroxidase and/or thyroglobulin antibodies) above 60 U/ml.
  
  
  RESULTS
  Establishing laboratory-specific gestational-age-dependent reference intervals, we found a prevalence of maternal thyroid dysfunction of 10%-15.8% by use of the cut-off suggested by the American Thyroid Association. Thyroid dysfunction was significantly associated with antibody-positivity (P<0.05). No associations were found between preterm delivery and thyroid dysfunction (adjusted OR 0.6, 95% CI: 0.1-2.3) or autoimmunity (adjusted OR 1.1, 95% CI: 0.4-2.7).
  
  
  CONCLUSIONS
  After the implementation of the Danish iodine fortification program, the prevalence of thyroid dysfunction and autoimmunity in Danish pregnant women is high - even higher by use of pre-established reference intervals from international consensus guidelines. However, no associations were found with abnormal obstetric outcome. Large randomized controlled trials are needed to clarify the benefit of treating slight aberrations in pregnant women's thyroid function.
authors: Departments of Medical EndocrinologySection 2132Growth and ReproductionClinical BiochemistryCopenhagen University Hospital (Rigshopitalet), Blegdamsvej 9, 2100 Copenhagen, DenmarkDepartment of Clinical BiochemistrySlagelse-Naestved Hospital, Naestved, DenmarkDepartment of ObstetricsCenter of Fetal Medicine, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark sofiebliddal@gmail.com.
authors: Sofie
authors: S
authors: Bliddal
authors: Departments of Medical EndocrinologySection 2132Growth and ReproductionClinical BiochemistryCopenhagen University Hospital (Rigshopitalet), Blegdamsvej 9, 2100 Copenhagen, DenmarkDepartment of Clinical BiochemistrySlagelse-Naestved Hospital, Naestved, DenmarkDepartment of ObstetricsCenter of Fetal Medicine, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark.
authors: Malene
authors: M
authors: Boas
authors: Departments of Medical EndocrinologySection 2132Growth and ReproductionClinical BiochemistryCopenhagen University Hospital (Rigshopitalet), Blegdamsvej 9, 2100 Copenhagen, DenmarkDepartment of Clinical BiochemistrySlagelse-Naestved Hospital, Naestved, DenmarkDepartment of ObstetricsCenter of Fetal Medicine, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark.
authors: Linda
authors: L
authors: Hilsted
authors: Departments of Medical EndocrinologySection 2132Growth and ReproductionClinical BiochemistryCopenhagen University Hospital (Rigshopitalet), Blegdamsvej 9, 2100 Copenhagen, DenmarkDepartment of Clinical BiochemistrySlagelse-Naestved Hospital, Naestved, DenmarkDepartment of ObstetricsCenter of Fetal Medicine, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark.
authors: Lennart
authors: L
authors: Friis-Hansen
authors: Departments of Medical EndocrinologySection 2132Growth and ReproductionClinical BiochemistryCopenhagen University Hospital (Rigshopitalet), Blegdamsvej 9, 2100 Copenhagen, DenmarkDepartment of Clinical BiochemistrySlagelse-Naestved Hospital, Naestved, DenmarkDepartment of ObstetricsCenter of Fetal Medicine, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark.
authors: Ann
authors: A
authors: Tabor
authors: Departments of Medical EndocrinologySection 2132Growth and ReproductionClinical BiochemistryCopenhagen University Hospital (Rigshopitalet), Blegdamsvej 9, 2100 Copenhagen, DenmarkDepartment of Clinical BiochemistrySlagelse-Naestved Hospital, Naestved, DenmarkDepartment of ObstetricsCenter of Fetal Medicine, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark.
authors: Ulla
authors: U
authors: Feldt-Rasmussen
mesh_terms: D000328:Adult; D001323:Autoantibodies / Q000276:immunology*; D015551:Autoimmunity; D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D005260:Female; D005527:Food, Fortified; D005865:Gestational Age; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood / Q000453:epidemiology / Q000276:immunology; D007037:Hypothyroidism / Q000097:blood / Q000453:epidemiology / Q000276:immunology; D007453:Iodide Peroxidase / Q000276:immunology; D007455:Iodine; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood / Q000453:epidemiology* / Q000276:immunology; D047928:Premature Birth / Q000453:epidemiology*; D015995:Prevalence; D013959:Thyroid Diseases / Q000097:blood / Q000453:epidemiology* / Q000276:immunology; D013960:Thyroid Function Tests; D013967:Thyroiditis, Autoimmune / Q000097:blood / Q000453:epidemiology / Q000276:immunology; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
chemical_list: D001323:Autoantibodies; C006606:anti-thyroglobulin; D014284:Triiodothyronine; D013972:Thyrotropin; D007455:Iodine; D007453:Iodide Peroxidase; D013974:Thyroxine