Sequential first- and second-trimester TSH, free thyroxine, and thyroid antibody measurements in women with known hypothyroidism: a FaSTER trial study.
OBJECTIVE
The purpose of this study was to examine how closely hypothyroidism management in the general pregnancy population satisfies recently issued guidelines and to determine whether improvements are indicated.


METHODS
This was an observational study in which women at 5 recruitment centers in the first- and second-trimester evaluation of risk for aneuploidy trial allowed the use of sequentially obtained first- and second-trimester sera for additional research. Three hundred eighty-nine women had hypothyroidism by self-report. Thyroid-related measurements were performed on all samples between July 2004 and May 2005.


RESULTS
Forty-three percent of the thyroid-stimulating hormone (TSH) values are at or above recently recommended guidelines in the first trimester (2.5 mU/L), as opposed to 33% of the values in the second trimester (3.0 mU/L). Twenty percent of the TSH values are at or above a less restrictive 98th percentile of normal in the first trimester, as opposed to 23% of the values in the second trimester. Mean TSH levels are higher in women with antibodies. Free thyroxine values are unremarkable.


CONCLUSIONS
Future strategies should focus on more effectively treating women with hypothyroidism who have persistently elevated TSH values.
McClain
Monica R
MR
Warren Alpert Medical School, Brown University, Providence, RI 02903, USA.
Lambert-Messerlian
Geralyn
G
Haddow
James E
JE
Palomaki
Glenn E
GE
Canick
Jacob A
JA
Cleary-Goldman
Jane
J
Malone
Fergal D
FD
Porter
T Flint
TF
Nyberg
David A
DA
Bernstein
Peter
P
D'Alton
Mary E
ME
D000328:Adult; D001323:Autoantibodies / Q000097:blood; D005260:Female; D017408:Guidelines as Topic; D006801:Humans; D007037:Hypothyroidism / Q000097:blood*; D017410:Practice Guidelines as Topic; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood*; D011261:Pregnancy Trimester, First / Q000097:blood*; D011262:Pregnancy Trimester, Second / Q000097:blood*; D013972:Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000097:blood*
D001323:Autoantibodies; C006606:anti-thyroglobulin; D013972:Thyrotropin; D013974:Thyroxine