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Journal of Thyroid Research
Volume 2011, Article ID 905734, 7 pages
Research Article

Free Thyroxine Level in the High Normal Reference Range Prescribed for Nonpregnant Women May Reduce the Preterm Delivery Rate in Multiparous

1Praxis für Gynäkologie und Geburtshilfe, Marktplatz 29, 88416 Ochsenhausen, Germany
2Frauenklinik des Klinikums Memmingen, Klinikum Memmingen, Bismarckstraße 23, 87700 Memmingen, Germany
3Institut Forschung, Beratung und Evaluation, FB+E Forschung, Beratung Evaluation GmbH, Postfach 10 03 35, 10563 Berlin, Germany

Received 18 August 2011; Revised 23 October 2011; Accepted 24 October 2011

Academic Editor: Noriyuki Koibuchi

Copyright © 2011 P. Torremante et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Preterm birth is the most common reason for perinatal morbidity and mortality in the western world. It has been shown that in euthyreotic pregnant women with thyroid autoimmune antibodies, L-Thyroxine replacement reduces preterm delivery rate in singleton pregnancies. We investigated in a nonrandomized retrospective observational study whether L-Thyroxine replacement, maintaining maternal free thyroxine serum level in the high normal reference range prescribed for nonpregnant women also influences the rate of preterm delivery in women without thyroid autoimmune antibodies. As control group for preterm delivery rate, data from perinatal statistics of the State of Baden-Württemberg from 2006 were used. The preterm delivery rate in the study group was significantly reduced. The subgroup analysis shows no difference in primiparous but a decline in multiparous by approximately 61% with L-Thyroxine replacement. Maintaining free thyroxine serum level in the high normal reference range prescribed for nonpregnant women may reduce the preterm delivery rate.