Mid-gestational maternal free thyroxine concentration and offspring neurocognitive development at age two years.
BACKGROUND
Lower neurocognitive development scores at age 2 yr have been reported in association with euthyroid hypothyroxinemia during early pregnancy.


OBJECTIVE
The objective of this study was to further explore this association with euthyroid hypothyroxinemia during early pregnancy.


METHODS
This was an observational, nested case-control study.


METHODS
The study was conducted at physician offices and prenatal clinics throughout Maine.


METHODS
Between May 2004 and March 2006, TSH was measured in 5734 women in conjunction with second-trimester Down syndrome screening. After completion of pregnancy, free T(4) was measured in stored second-trimester sera from euthyroid women (TSH 0.1-3.5 mIU/ml; n = 5560). Women with free T(4) at the third centile or less (n = 99) were matched with women whose free T(4) was at the 10th to the 90th centile (n = 99).


METHODS
There were no interventions.


METHODS
Bayley Scales of Infant Development (BSID III) were administered to the 198 offspring at age 2 yr. Scores for cognitive, language, and motor development were compared between matched pairs of offspring from the two groups before and after correcting for relevant variables.


RESULTS
Unadjusted BSID-III scores (cognitive, language, and motor) were lower by about 3% at age 2 yr among offspring of 98 hypothyroxinemic women (cases), reaching borderline significance for cognitive and motor scores. After adjustment for gestational age, the child's age at testing, maternal weight, and education, all differences diminished and became nonsignificant. Scores less than 85 were more frequent among case children but did not reach statistical significance (P = 0.14).


CONCLUSIONS
Isolated hypothyroxinemia during the second trimester is not associated with significantly lower BSID-III scores at age 2 yr, compared with scores for offspring of matched euthyroxinemic women.
Foundation for Blood Research, 8 Science Park Road, Scarborough, Maine 04074, USA. wcraig@fbr.org
Wendy Y
WY
Craig
Walter C
WC
Allan
Edward M
EM
Kloza
Andrea J
AJ
Pulkkinen
Susan
S
Waisbren
Daniel I
DI
Spratt
Glenn E
GE
Palomaki
Louis M
LM
Neveux
James E
JE
Haddow
D000328:Adult; D000367:Age Factors; D001921:Brain / Q000254:growth & development*; D016022:Case-Control Studies; D002648:Child; D002657:Child Development / Q000502:physiology*; D016241:Child of Impaired Parents / Q000523:psychology; D002675:Child, Preschool; D003071:Cognition / Q000502:physiology*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009035:Mothers; D009994:Osmolar Concentration; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood; D011262:Pregnancy Trimester, Second / Q000097:blood*; D011297:Prenatal Exposure Delayed Effects / Q000097:blood / Q000523:psychology; D013959:Thyroid Diseases / Q000097:blood; D013974:Thyroxine / Q000097:blood* / Q000737:chemistry
D013974:Thyroxine