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Pregnant Women on Thyroxine Substitution Are Often Dysregulated in Early Pregnancy.

Hallengren, Bengt LU ; Lantz, Mikael LU ; Andréasson, Bengt LU and Grennert, Lars LU (2009) In Thyroid 19. p.391-394
Abstract
Background: Thyroid hormones are important for normal fetal development. Maternal hypothyroidism during early pregnancy is associated with impaired neuropsychological development of children and other adverse outcomes. The primary aim of this prospective study was to determine whether thyroxine-treated pregnant women with hypothyroidism are adequately thyroxine substituted in early pregnancy. A secondary aim was to determine if fetal loss differed between females with thyrotropin (TSH) values within and outside the reference range at their first TSH test, scheduled for 1-2 weeks after verification of pregnancy. Methods: This was a prospective open-labeled study. During the years 1997-2002, 119 consecutive pregnancies in 101 females with... (More)
Background: Thyroid hormones are important for normal fetal development. Maternal hypothyroidism during early pregnancy is associated with impaired neuropsychological development of children and other adverse outcomes. The primary aim of this prospective study was to determine whether thyroxine-treated pregnant women with hypothyroidism are adequately thyroxine substituted in early pregnancy. A secondary aim was to determine if fetal loss differed between females with thyrotropin (TSH) values within and outside the reference range at their first TSH test, scheduled for 1-2 weeks after verification of pregnancy. Methods: This was a prospective open-labeled study. During the years 1997-2002, 119 consecutive pregnancies in 101 females with thyroid diseases were followed at the Department of Endocrinology, Malmö University Hospital. At the first visit, 63 patients, median age 30 years (range 17-45 years), were on thyroxine substitution therapy for hypothyroidism. In these patients 83% were in their first trimester at the time of the initial test. Results: Of the 63 patients on thyroxine substitution for hypothyroidism 32 (51%; Group A) patients had serum TSH values within the reference range at their initial test and 31 (49%; Group B) had serum TSH values outside the reference range. Twelve (19%) had TSH values of <0.40 mIU/L and 19 (30%) had TSH values of >4.0 mIU/l. The fetal loss was 2 of 32 (6%) in Group A compared to 9 of 31 (29%) in Group B (p < 0.05). Conclusions: In 49% of pregnant women on thyroxine substitution, serum TSH values were outside the reference range when first tested, generally in the first trimester. Fetal loss was significantly greater in pregnant women with abnormal TSH values compared to those with normal TSH values. Thyroid function in pregnant women on thyroxine substitution should be monitored early in pregnancy and carefully followed during pregnancy. The thyroxine dose should be increased as needed early in pregnancy to avoid hypothyroidism. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Thyroid
volume
19
pages
391 - 394
publisher
Mary Ann Liebert, Inc.
external identifiers
  • WOS:000265000300011
  • PMID:19207005
  • Scopus:66749122989
ISSN
1557-9077
DOI
10.1089/thy.2008.0206
language
English
LU publication?
yes
id
1629a0ea-bf0e-4187-b8eb-08fc89a98ff3 (old id 1302716)
alternative location
http://www.ncbi.nlm.nih.gov/pubmed/19207005?dopt=Abstract
date added to LUP
2009-03-05 16:32:46
date last changed
2016-11-27 04:29:44
@misc{1629a0ea-bf0e-4187-b8eb-08fc89a98ff3,
  abstract     = {Background: Thyroid hormones are important for normal fetal development. Maternal hypothyroidism during early pregnancy is associated with impaired neuropsychological development of children and other adverse outcomes. The primary aim of this prospective study was to determine whether thyroxine-treated pregnant women with hypothyroidism are adequately thyroxine substituted in early pregnancy. A secondary aim was to determine if fetal loss differed between females with thyrotropin (TSH) values within and outside the reference range at their first TSH test, scheduled for 1-2 weeks after verification of pregnancy. Methods: This was a prospective open-labeled study. During the years 1997-2002, 119 consecutive pregnancies in 101 females with thyroid diseases were followed at the Department of Endocrinology, Malmö University Hospital. At the first visit, 63 patients, median age 30 years (range 17-45 years), were on thyroxine substitution therapy for hypothyroidism. In these patients 83% were in their first trimester at the time of the initial test. Results: Of the 63 patients on thyroxine substitution for hypothyroidism 32 (51%; Group A) patients had serum TSH values within the reference range at their initial test and 31 (49%; Group B) had serum TSH values outside the reference range. Twelve (19%) had TSH values of &lt;0.40 mIU/L and 19 (30%) had TSH values of &gt;4.0 mIU/l. The fetal loss was 2 of 32 (6%) in Group A compared to 9 of 31 (29%) in Group B (p &lt; 0.05). Conclusions: In 49% of pregnant women on thyroxine substitution, serum TSH values were outside the reference range when first tested, generally in the first trimester. Fetal loss was significantly greater in pregnant women with abnormal TSH values compared to those with normal TSH values. Thyroid function in pregnant women on thyroxine substitution should be monitored early in pregnancy and carefully followed during pregnancy. The thyroxine dose should be increased as needed early in pregnancy to avoid hypothyroidism.},
  author       = {Hallengren, Bengt and Lantz, Mikael and Andréasson, Bengt and Grennert, Lars},
  issn         = {1557-9077},
  language     = {eng},
  pages        = {391--394},
  publisher    = {ARRAY(0x8c3a910)},
  series       = {Thyroid},
  title        = {Pregnant Women on Thyroxine Substitution Are Often Dysregulated in Early Pregnancy.},
  url          = {http://dx.doi.org/10.1089/thy.2008.0206},
  volume       = {19},
  year         = {2009},
}