title: Variations of urinary iodine during the first trimester of pregnancy in an iodine-replete area. Comparison with non-pregnant women.
abstract: OBJECTIVE
  To assess variations of urinary iodine concentration (UIC) during a 4-week period among pregnant and non-pregnant women in an iodine-replete area.
  
  
  METHODS
  Pregnant (in their first trimester of pregnancy) and non-pregnant women referred to two maternity hospitals in Tehran were consecutively recruited from September 2005 to March 2006. Urine samples (5-10 mL) were collected on an every-other-day basis for 4 weeks (i.e., 12 samples for each individual). UIC was determined using a modified Sandell-Kolthoff method.
  
  
  RESULTS
  Thirty-six pregnant and 32 non-pregnant women completed the study. Mean±SD age of pregnant women was 27.4±6.4 and of non-pregnant women 27.6±4.5 years (P=0.897). Mean±SD gestational age was 11±3.3 weeks in pregnant participants. Median UIC of <100, 100-149, 150-249, and ≥250 µg/L was present in 19.4, 25, 30.6, and 25% of pregnant, 15.6, 37.5, 34.4, and 12.5% of non-pregnant, and 17.6, 30.9, 32.4, and 19.1% of total individuals, respectively. Median UIC values of samples numbers 1 to 12 were not significantly different either in pregnant (P=0.591) or in non-pregnant subjects (P=0.745). Except for sample number 11, median UIC was not significantly different between pregnant versus non-pregnant women (P values >0.05). Mean SD values for UIC in samples numbers 1 to 12 in pregnant women was 138.4 (24.1-404) and in non-pregnant women 118 (29.5-272.4) µg/L (P=0.286).
  
  
  CONCLUSIONS
  There was a wide intrapersonal variation in UIC values among pregnant and non-pregnant women residing in an iodine-replete area, supporting the notion that casual UIC would not reflect the iodine status of the individual.
authors.affiliation: Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Atieh
authors.initials: A
authors.lastname: Amouzegar
authors.forename: Fereidoun
authors.initials: F
authors.lastname: Azizi
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000652:urine; D016022:Case-Control Studies; D004032:Diet; D005260:Female; D006771:Hospitals, Maternity; D006801:Humans; D007455:Iodine / Q000652:urine*; D007492:Iran; D015596:Nutrition Assessment; D009752:Nutritional Status; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000652:urine*; D039401:Prenatal Nutritional Physiological Phenomena; D013997:Time Factors; D055815:Young Adult
chemical_list: D015415:Biomarkers; D007455:Iodine