title: Reference intervals in evaluation of maternal thyroid function of Manipuri women.
abstract: BACKGROUND
  The population of Manipur is of different ethnic background from the rest of the country. Several authors have suggested population/ethnic and laboratory specific reference range of maternal thyroid profile of different trimesters.
  
  
  OBJECTIVE
  To find the reference range of thyroid stimulating hormone (TSH), total thyroxine (TT4) and total tri-iodothyronine (TT3) levels for normal pregnant women of native Manipur descendants.
  
  
  METHODS
  The cross-sectional study was conducted at a teaching Institute after ethical clearance was obtained.
  
  
  METHODS
  A reference populations of 375 normal pregnant women were established after screening about 600 pregnant women. The study excluded patients with hyperemesis gravid arum, past history or family history of thyroid disorders as well as the connective tissue disorders, WHO grade 1 or 2 goiter, or any medications that alter thyroid functions. The serum levels of TSH, TT4, and TT3 were measured using chemiluminescence assay.
  
  
  METHODS
  Data for TT3 and TT4 were expressed as mean ± standard deviation, median and 5-95(th) percentiles.
  
  
  RESULTS
  The mean TSH in the three trimesters was 1.06 + 0.45, 1.23 + 0.30, and 1.25 + 0.36, respectively. The normal reference range thus was different from that of the kit reference range. On comparing to the Indian normative reference for the pregnant women, our results were not similar. However, the values were near similar to that of the American Thyroid Association guidelines.
  
  
  CONCLUSIONS
  We conclude our study results with a new reference range for the pregnant population in Manipur and also emphasis the use of trimester-specific reference range of thyroid hormone.
authors.affiliation: Department of General Medicine, Regional Institute of Medical Sciences, Imphal, Manipur, India.
authors.forename: Felix K
authors.initials: FK
authors.lastname: Jebasingh
authors.affiliation: Department of General Medicine, Regional Institute of Medical Sciences, Imphal, Manipur, India.
authors.forename: Ranabir
authors.initials: R
authors.lastname: Salam
authors.affiliation: Department of Obstetrics and Gynaecology, Regional Institute of Medical Sciences, Imphal, Manipur, India.
authors.forename: Trinity Laishram
authors.initials: TL
authors.lastname: Meetei
authors.affiliation: Department of General Medicine, Regional Institute of Medical Sciences, Imphal, Manipur, India.
authors.forename: Premchand Thangjam
authors.initials: PT
authors.lastname: Singh
authors.affiliation: Department of Obstetrics and Gynaecology, Regional Institute of Medical Sciences, Imphal, Manipur, India.
authors.forename: Nabakishore Naorem
authors.initials: NN
authors.lastname: Singh
authors.affiliation: Department of General Medicine, Regional Institute of Medical Sciences, Imphal, Manipur, India.
authors.forename: Lallan
authors.initials: L
authors.lastname: Prasad
keywords: Pregnancy; reference range; thyroid hormones