title: Prevalence of thyroid autoimmunity and dysfunction in women with iron deficiency during early pregnancy: is it altered?
abstract: OBJECTIVE
  Thyroid disorders and iron deficiency (ID) are associated with obstetrical and fetal complications. Iron is essential for the normal functioning of thyroid peroxidase (TPO-abs) and ID is frequent during pregnancy. The aim of this study was to compare the prevalence of thyroid autoimmunity (TAI) and dysfunction during the first trimester of pregnancy in women with and without ID.
  
  
  METHODS
  Cross-sectional data analysis of 1900 pregnant women nested within an ongoing prospective collection of pregnant women's data.
  
  
  METHODS
  The study was performed in a single, tertiary referral center. During the first antenatal visit, ferritin, TPO-abs, thyroid-stimulating hormone (TSH) and free T4 (FT4) were measured and age and BMI were recorded. ID was defined as ferritin <15µg/L, TAI when TPO-abs was >60kIU/L, and subclinical hypothyroidism (SCH) when TSH was >2.5mIU/L.
  
  
  RESULTS
  ID was present in 35% of women. Age and BMI were comparable between both groups. In the ID group, the prevalence of TAI and SCH was significantly higher, compared with that in the non-ID group (10% vs 6% and 20% vs 16%; P=0.011 and 0.049 respectively). Ferritin was inversely correlated with serum TSH (ρ=-0.076; P=0.001) and positive with FT4 levels (ρ=0.112; P<0.001). In the logistic regression model, ID remained associated with TAI after correction for confounding factors (P=0.017). The association with SCH was absent after correction for the confounders in the logistic regression model (P=0.082), but remained present in the linear regression model (P=0.035).
  
  
  CONCLUSIONS
  ID was frequent during the first trimester of pregnancy and was associated with a higher prevalence of TAI, higher serum TSH, and lower FT4 levels.
authors.affiliation: Endocrine Unit.
authors.forename: Flora
authors.initials: F
authors.lastname: Veltri
authors.affiliation: Department of Gynecology and Obstetrics.
authors.forename: Sarah
authors.initials: S
authors.lastname: Decaillet
authors.affiliation: Endocrine Unit.
authors.forename: Pierre
authors.initials: P
authors.lastname: Kleynen
authors.affiliation: Endocrine Unit.
authors.forename: Lidia
authors.initials: L
authors.lastname: Grabczan
authors.affiliation: Department of Gynecology and Obstetrics.
authors.forename: Julie
authors.initials: J
authors.lastname: Belhomme
authors.affiliation: Department of Gynecology and Obstetrics.
authors.forename: Serge
authors.initials: S
authors.lastname: Rozenberg
authors.affiliation: Geriatric UnitCentre Hosptilalier Universitaire Saint Pierre, Université Libre de Bruxelles (ULB), Brussels, Belgium.
authors.forename: Thierry
authors.initials: T
authors.lastname: Pepersack
authors.affiliation: Endocrine Unit kris_poppe@stpierre-bru.be.
authors.forename: Kris
authors.initials: K
authors.lastname: Poppe
mesh_terms: D000328:Adult; D018798:Anemia, Iron-Deficiency / Q000097:blood / Q000453:epidemiology* / Q000503:physiopathology; D001327:Autoimmune Diseases / Q000097:blood / Q000453:epidemiology* / Q000503:physiopathology; D015897:Comorbidity; D003430:Cross-Sectional Studies; D005260:Female; D005293:Ferritins / Q000097:blood; D006801:Humans; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood / Q000453:epidemiology* / Q000503:physiopathology; D011261:Pregnancy Trimester, First; D015995:Prevalence; D013959:Thyroid Diseases / Q000097:blood / Q000453:epidemiology* / Q000503:physiopathology; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood
chemical_list: D013972:Thyrotropin; D005293:Ferritins; D013974:Thyroxine