10027/8555
Roberto Negro
Roberto
Negro
Alan Schwartz
Alan
Schwartz
Riccardo Gismondi
Riccardo
Gismondi
Andrea Tinelli
Andrea
Tinelli
Tiziana Mangieri
Tiziana
Mangieri
Alex Stagnaro-Green
Alex
Stagnaro-Green
Increased Pregnancy Loss Rate in Thyroid Antibody Negative Women with TSH Levels between 2.5 and 5.0 in the First Trimester of Pregnancy
University of Illinois at Chicago
2012
untagged
2012-08-18 00:00:00
Journal contribution
https://indigo.uic.edu/articles/journal_contribution/Increased_Pregnancy_Loss_Rate_in_Thyroid_Antibody_Negative_Women_with_TSH_Levels_between_2_5_and_5_0_in_the_First_Trimester_of_Pregnancy/10778951
Context: The definition of what constitutes a normal TSH during pregnancy is in flux. Recent studies suggested that the first trimester upper limit of normal for TSH should be 2.5 mIU/liter.
Objective: The objective of the study was to evaluate the pregnancy loss and preterm delivery rate in first-trimester thyroid peroxidase antibody-negative women with TSH values between 2.5 and 5.0 mIU/liter.
Design: The present study is a component of a recently published large-scale prospective trial that evaluated the impact of levothyroxine treatment on maternal and neonatal complications in thyroid peroxidase-positive women with TSH levels above 2.5 mIU/liter. The present study evaluated
4123 thyroid peroxidase antibody-negative women with TSH levels at or below 5.0 mIU/liter. Women were divided into two groups based on their initial TSH: group A, TSH level below 2.5 mIU/liter, excluding hyperthyroid women defined as an undetectable TSH with an elevated free T4, and group B, TSH level between 2.5 and 5.0 mIU/liter.
Setting: The study was conducted at two ambulatory clinics of community hospitals in southern Italy.
Patients: A total of 4123 women were evaluated.
Intervention: There was no intervention.
Main Outcome Measures: The incidence of pregnancy loss and preterm delivery in group A as compared with group B was measured.
Results: The rate of pregnancy loss was significantly higher in group B as compared with group A (6.1 vs. 3.6% respectively, P 0.006). There was no difference in the rate of preterm delivery between the two groups.
Conclusions: The increased incidence of pregnancy loss in pregnant women with TSH levels between 2.5 and 5.0 mIU/liter provides strong physiological evidence to support redefining the TSH upper limit of normal in the first trimester to 2.5 mIU/liter. (J Clin Endocrinol Metab 95: E44–E48, 2010)