First- and second-trimester thyroid hormone reference data in pregnant women: a FaSTER (First- and Second-Trimester Evaluation of Risk for aneuploidy) Research Consortium study.

Abstract

OBJECTIVE:

The purpose of this study was to calculate first and second trimester reference ranges and within-woman correlations for TSH, free T4, and thyroid antibodies.

STUDY DESIGN:

TSH, free T4, and thyroid antibodies were measured in paired sera from 9562 women in the FaSTER trial of Down syndrome screening.

RESULTS:

The median first trimester TSH (1.05 mIU/L) is lower than the second (1.23 mIU/L); and 98th centile is higher (4.15 vs 3.77 mIU/L). Within-woman paired TSH correlations are moderately strong (r(2) = 0.64). Among women with first trimester TSH values above the 98th centile, second trimester values are over the 95th centile in 68%. Median first trimester free T4 values (1.10 ng/dL) are higher than second (1.01 ng/dL). Paired free T4 measurements correlate weakly (r(2) = 0.23). Among women with first trimester free T4 values below the 2nd centile, second trimester values are below the 5th centile in 32%. Antibody measurements correlate strongly between trimesters (thyroperoxidase r(2) = 0.79, thyroglobulin r(2) = 0.83).

CONCLUSION:

TSH and free T4 measurements require gestation-specific reference ranges.

• Authors: Geralyn Lambert-Messerlian, Monica McClain, James E Haddow, Glenn E Palomaki, Jacob A Canick, Jane Cleary-Goldman, Fergal D Malone, T Flint Porter, David A Nyberg, Peter Bernstein, Mary E D'Alton, FaSTER Research Consortium
• Journal: American journal of obstetrics and gynecology (Am J Obstet Gynecol) Vol. 199 Issue 1 Pg. 62.e1-6 (Jul 2008) ISSN: 1097-6868 [Electronic] United States
• PMID: 18585522 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)

Chemical References

• Autoantibodies
• anti-thyroglobulin
• Thyrotropin
• Thyroxine

Topics

• Adult
• Autoantibodies (blood)
• Female
• Gestational Age
• Humans
• Pregnancy
• Pregnancy Trimester, First (blood)
• Pregnancy Trimester, Second (blood)
• Reference Values
• Thyrotropin (blood)
• Thyroxine (blood)