title: Thyroid hormone treatment among pregnant women with subclinical hypothyroidism: US national assessment.
abstract: OBJECTIVE
  To estimate the effectiveness and safety of thyroid hormone treatment among pregnant women with subclinical hypothyroidism.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  Large US administrative database between 1 January 2010 and 31 December 2014.
  
  
  METHODS
  5405 pregnant women with subclinical hypothyroidism, defined as untreated thyroid stimulating hormone (TSH) concentration 2.5-10 mIU/L.
  
  
  METHODS
  Thyroid hormone therapy.
  
  
  METHODS
  Pregnancy loss and other pre-specified maternal and fetal pregnancy related adverse outcomes.
  
  
  RESULTS
  Among 5405 pregnant women with subclinical hypothyroidism, 843 with a mean pre-treatment TSH concentration of 4.8 (SD 1.7) mIU/L were treated with thyroid hormone and 4562 with a mean baseline TSH concentration of 3.3 (SD 0.9) mIU/L were not treated (P<0.01). Pregnancy loss was significantly less common among treated women (n=89; 10.6%) than among untreated women (n=614; 13.5%) (P<0.01). Compared with the untreated group, treated women had lower adjusted odds of pregnancy loss (odds ratio 0.62, 95% confidence interval 0.48 to 0.82) but higher odds of preterm delivery (1.60, 1.14 to 2.24), gestational diabetes (1.37, 1.05 to 1.79), and pre-eclampsia (1.61, 1.10 to 2.37); other pregnancy related adverse outcomes were similar between the two groups. The adjusted odds of pregnancy loss were lower in treated women than in untreated women if their pre-treatment TSH concentration was 4.1-10 mIU/L (odds ratio 0.45, 0.30 to 0.65) but not if it was 2.5-4.0 mIU/L (0.91, 0.65 to 1.23) (P<0.01).
  
  
  CONCLUSIONS
  Thyroid hormone treatment was associated with decreased risk of pregnancy loss among women with subclinical hypothyroidism, especially those with pre-treatment TSH concentrations of 4.1-10 mIU/L. However, the increased risk of other pregnancy related adverse outcomes calls for additional studies evaluating the safety of thyroid hormone treatment in this patient population.
authors.affiliation: Division of Endocrinology and Metabolism, Center for Osteoporosis and Metabolic Bone Diseases, University of Arkansas for Medical Sciences and the Central Arkansas Veterans Health Care System, Little Rock, AR 72205, USA.|Knowledge and Evaluation Research Unit in Endocrinology (KER_Endo), Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Spyridoula
authors.initials: S
authors.lastname: Maraka
authors.affiliation: Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Raphael
authors.initials: R
authors.lastname: Mwangi
authors.affiliation: Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery, Mayo Clinic, Rochester, MN 55905, USA mccoy.rozalina@mayo.edu.|Division of Primary Care Internal Medicine, Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Rozalina G
authors.initials: RG
authors.lastname: McCoy
authors.affiliation: Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery, Mayo Clinic, Rochester, MN 55905, USA.|Division of Health Care Policy and Research, Department of Health Services Research, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Xiaoxi
authors.initials: X
authors.lastname: Yao
authors.affiliation: Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery, Mayo Clinic, Rochester, MN 55905, USA.|Optum Labs, Cambridge, MA 02142, USA.
authors.forename: Lindsey R
authors.initials: LR
authors.lastname: Sangaralingham
authors.affiliation: Knowledge and Evaluation Research Unit in Endocrinology (KER_Endo), Mayo Clinic, Rochester, MN 55905, USA.|Division of Endocrinology, Department of Medicine, University of Florida, Gainesville, FL 32610, USA.
authors.forename: Naykky M
authors.initials: NM
authors.lastname: Singh Ospina
authors.affiliation: Division of Endocrinology, Department of Medicine, National University of Ireland, Galway, Ireland.|Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Derek T
authors.initials: DT
authors.lastname: O'Keeffe
authors.affiliation: Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Ana E Espinosa
authors.initials: AE
authors.lastname: De Ycaza
authors.affiliation: Knowledge and Evaluation Research Unit in Endocrinology (KER_Endo), Mayo Clinic, Rochester, MN 55905, USA.|Division of Endocrinology, Department of Internal Medicine, University Hospital "Dr. Jose E. Gonzalez," Autonomous University of Nuevo Leon, Monterrey, 64460, Mexico.
authors.forename: Rene
authors.initials: R
authors.lastname: Rodriguez-Gutierrez
authors.affiliation: Department of Obstetrics and Gynecology, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Charles C
authors.initials: CC
authors.lastname: Coddington
authors.affiliation: Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Marius N
authors.initials: MN
authors.lastname: Stan
authors.affiliation: Knowledge and Evaluation Research Unit in Endocrinology (KER_Endo), Mayo Clinic, Rochester, MN 55905, USA.|Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Juan P
authors.initials: JP
authors.lastname: Brito
authors.affiliation: Knowledge and Evaluation Research Unit in Endocrinology (KER_Endo), Mayo Clinic, Rochester, MN 55905, USA.|Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Victor M
authors.initials: VM
authors.lastname: Montori
mesh_terms: D000293:Adolescent; D000328:Adult; D058070:Asymptomatic Diseases; D016208:Databases, Factual; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007037:Hypothyroidism / Q000188:drug therapy*; D016015:Logistic Models; D008875:Middle Aged; D015999:Multivariate Analysis; D011247:Pregnancy; D011248:Pregnancy Complications / Q000188:drug therapy*; D012189:Retrospective Studies; D013963:Thyroid Hormones / Q000627:therapeutic use*; D016896:Treatment Outcome; D014481:United States; D055815:Young Adult
chemical_list: D013963:Thyroid Hormones