Maternal thyroid hypofunction and pregnancy outcome.
OBJECTIVE
To estimate whether maternal thyroid hypofunction is associated with complications.


METHODS
A total of 10,990 patients had first- and second-trimester serum assayed for thyroid-stimulating hormone (TSH), free thyroxine (freeT4), and antithyroglobulin and antithyroid peroxidase antibodies. Thyroid hypofunction was defined as 1) subclinical hypothyroidism: TSH levels above the 97.5th percentile and free T4 between the 2.5th and 97.5th percentiles or 2) hypothyroxinemia: TSH between the 2.5th and 97.5th percentiles and free T4 below the 2.5th percentile. Adverse outcomes were evaluated. Patients with thyroid hypofunction were compared with euthyroid patients (TSH and free T4 between the 2.5th and 97.5th percentiles). Patients with and without antibodies were compared. Multivariable logistic regression analysis adjusted for confounders was used.


RESULTS
Subclinical hypothyroidism was documented in 2.2% (240 of 10,990) in the first and 2.2% (243 of 10,990) in the second trimester. Hypothyroxinemia was documented in 2.1% (232 of 10,990) in the first and 2.3% (247 of 10,990) in the second trimester. Subclinical hypothyroidism was not associated with adverse outcomes. In the first trimester, hypothyroxinemia was associated with preterm labor (adjusted odds ratio [aOR] 1.62; 95% confidence interval [CI] 1.00-2.62) and macrosomia (aOR 1.97; 95% CI 1.37-2.83). In the second trimester, it was associated with gestational diabetes (aOR 1.7; 95% CI 1.02-2.84). Fifteen percent (1,585 of 10,990) in the first and 14% (1,491 of 10,990) in the second trimester had antithyroid antibodies. When both antibodies were positive in either trimester, there was an increased risk for preterm premature rupture of membranes (P=.002 and P<.001, respectively).


CONCLUSIONS
Maternal thyroid hypofunction is not associated with a consistent pattern of adverse outcomes.


METHODS
II.
Cleary-Goldman
Jane
J
Columbia University Medical Center, New York, NY, USA. jcgoldman@mfmnyc.com
Malone
Fergal D
FD
Lambert-Messerlian
Geralyn
G
Sullivan
Lisa
L
Canick
Jacob
J
Porter
T Flint
TF
Luthy
David
D
Gross
Susan
S
Bianchi
Diana W
DW
D'Alton
Mary E
ME
D000328:Adult; D001323:Autoantibodies / Q000009:adverse effects; D005260:Female; D005322:Premature Rupture of Fetal Membranes / Q000209:etiology; D006801:Humans; D007037:Hypothyroidism / Q000150:complications* / Q000276:immunology; D016017:Odds Ratio; D011247:Pregnancy; D011248:Pregnancy Complications / Q000276:immunology; D011256:Pregnancy Outcome; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second; D012306:Risk; D013954:Thyroglobulin / Q000009:adverse effects; D013960:Thyroid Function Tests
D001323:Autoantibodies; C006606:anti-thyroglobulin; D013954:Thyroglobulin