title: Thyroid dysfunction and autoantibodies in early pregnancy are associated with increased risk of gestational diabetes and adverse birth outcomes.
abstract: BACKGROUND
  Maternal thyroid dysfunction, especially in early pregnancy, may lead to pregnancy complications and adverse birth outcomes. Few population-based prospective studies have evaluated these effects and results are discrepant.
  
  
  OBJECTIVE
  We examined the association of thyroid function and autoimmunity in early pregnancy with adverse pregnancy and birth outcomes.
  
  
  METHODS
  The study used data from the prospective mother-child cohort "Rhea" study in Crete, Greece. A total of 1170 women with singleton pregnancies participated in this analysis. Maternal serum samples in the first trimester of pregnancy were tested for thyroid hormones (TSH, free T(4), and free T(3)) and thyroid antibodies (thyroid peroxidase antibody and thyroglobulin antibody). Multivariable log-Poisson regression models were used adjusting for confounders.
  
  
  METHODS
  Outcomes included gestational diabetes, gestational hypertension/preeclampsia, cesarean section, preterm delivery, low birth weight, and small-for-gestational-age neonates.
  
  
  RESULTS
  The combination of high TSH and thyroid autoimmunity in early pregnancy was associated with a 4-fold increased risk for gestational diabetes [relative risk (RR) 4.3, 95% confidence interval (CI) 2.1-8.9)] and a 3-fold increased risk for low birth weight neonates (RR 3.1, 95% CI 1.2-8.0) after adjustment for several confounders. Women positive for thyroid antibodies without elevated TSH levels in early pregnancy were at high risk for spontaneous preterm delivery (RR 1.7, 95% CI 1.1-2.8), whereas the combined effect of high TSH and positive thyroid antibodies did not show an association with preterm birth.
  
  
  CONCLUSIONS
  High TSH levels and thyroid autoimmunity in early pregnancy may detrimentally affect pregnancy and birth outcomes.
authors.affiliation: Department of Social Medicine, Faculty of Medicine, University of Crete, P.O. Box 2208, Heraklion 71003, Crete, Greece.
authors.forename: Polyxeni
authors.initials: P
authors.lastname: Karakosta
authors.forename: Dimitris
authors.initials: D
authors.lastname: Alegakis
authors.forename: Vaggelis
authors.initials: V
authors.lastname: Georgiou
authors.forename: Theano
authors.initials: T
authors.lastname: Roumeliotaki
authors.forename: Eleni
authors.initials: E
authors.lastname: Fthenou
authors.forename: Maria
authors.initials: M
authors.lastname: Vassilaki
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Boumpas
authors.forename: Elias
authors.initials: E
authors.lastname: Castanas
authors.forename: Manolis
authors.initials: M
authors.lastname: Kogevinas
authors.forename: Leda
authors.initials: L
authors.lastname: Chatzi
mesh_terms: D000328:Adult; D001323:Autoantibodies / Q000097:blood*; D015331:Cohort Studies; D016640:Diabetes, Gestational / Q000097:blood / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D005865:Gestational Age; D006115:Greece / Q000453:epidemiology; D006801:Humans; D007231:Infant, Newborn; D036801:Parturition / Q000097:blood / Q000276:immunology / Q000502:physiology; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood* / Q000453:epidemiology*; D011256:Pregnancy Outcome / Q000453:epidemiology*; D011261:Pregnancy Trimester, First / Q000097:blood / Q000276:immunology; D011262:Pregnancy Trimester, Second / Q000097:blood / Q000276:immunology; D012307:Risk Factors; D013959:Thyroid Diseases / Q000097:blood / Q000453:epidemiology* / Q000276:immunology; D013960:Thyroid Function Tests / Q000706:statistics & numerical data; D055815:Young Adult
chemical_list: D001323:Autoantibodies