title: Decreased birth weight, length, and head circumference in children born by women years after treatment for hyperthyroidism.
abstract: BACKGROUND
  Whether hyperthyroidism influences the birth characteristics of children born several years after treatment is unknown.
  
  
  OBJECTIVE
  The objective of the study was to compare birth characteristics in singleton newborns delivered by women previously treated for Graves' disease (GD), toxic nodular goiter (TNG), or nontoxic goiter (NTG).
  
  
  METHODS
  This was a nested case-control design within a national cohort registry study from 1950 through 2006.
  
  
  METHODS
  The study was conducted at a university and a hospital center in collaboration.
  
  
  METHODS
  The birth characteristics of newborns (n = 3421) delivered in a cohort of 43 633 women treated for GD or toxic nodular goiter by radioiodine or surgery (exposed group) at least 1 year prior to pregnancy were compared with newborns (n = 2914) of 45 655 mothers, previously operated for NTG (unexposed group).
  
  
  RESULTS
  The primary outcome was birth weight, length, and head circumference. The secondary outcome was malformations, gestational age, and type of hyperthyroidism.
  
  
  RESULTS
  The birth weight of exposed children was 3431 ± 607 g (mean ± SD) compared with the unexposed, 3520 ± 641 g (P < .001). The cumulative odds ratio (OR) for lower birth weight was 1.29 [95% confidence interval (CI) 1.16-1.43]. The average birth length for the exposed children was 50.0 ± 2.7 cm compared with the unexposed of 50.4 cm ± 2.6 cm (P < .01) [cumulative OR 1.25 (95% CI 1.13-1.37)]. The head circumference was 34.5 ± 1.9 cm among exposed and 34.7 ± 1.8 cm, respectively (P < .001), with an OR of 1.24 (95% CI 1.13-1.35). No differences in birth characteristics were observed between children born after maternal GD or toxic nodular goiter.
  
  
  CONCLUSIONS
  Previous GD or TNG may influence the birth characteristics several years after radioiodine or surgical treatment.
authors.affiliation: Division of Endocrinology (H.O., O.Tö.), Department of Internal Medicine, Södersjukhuset, 11883, Stockholm, Sweden; Institution of Clinical Research and Education (O.Tö.), Department of Medical Epidemiology and Biostatistics (L.Y., A.N.I., P.H., S.L.), and Institution of Molecular Medicine and Surgery (M.A.-N., G.W.), Karolinska Institutet, 17177, Stockholm, Sweden; Department of Oncology (O.Tu.), Karolinska University Hospital, 171 76 Solna, Sweden; and Department of Research and Development (S.L.), Region Halland, 301 80 Halmstad, Sweden.
authors.forename: Hans
authors.initials: H
authors.lastname: Ohrling
authors.forename: Ove
authors.initials: O
authors.lastname: Törring
authors.forename: Li
authors.initials: L
authors.lastname: Yin
authors.forename: Anastasia N
authors.initials: AN
authors.lastname: Iliadou
authors.forename: Ove
authors.initials: O
authors.lastname: Tullgren
authors.forename: Mirna
authors.initials: M
authors.lastname: Abraham-Nordling
authors.forename: Göran
authors.initials: G
authors.lastname: Wallin
authors.forename: Per
authors.initials: P
authors.lastname: Hall
authors.forename: Stefan
authors.initials: S
authors.lastname: Lönn
mesh_terms: D016022:Case-Control Studies; D018568:Crown-Rump Length; D005260:Female; D005865:Gestational Age; D006044:Goiter, Nodular / Q000532:radiotherapy / Q000601:surgery; D006111:Graves Disease / Q000532:radiotherapy / Q000601:surgery; D006257:Head; D006801:Humans; D006980:Hyperthyroidism / Q000532:radiotherapy* / Q000601:surgery; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D011248:Pregnancy Complications / Q000209:etiology*; D011297:Prenatal Exposure Delayed Effects / Q000209:etiology*; D012042:Registries; D013971:Thyrotoxicosis / Q000532:radiotherapy / Q000601:surgery