Maternal thyroid disease, thyroid medication use, and selected birth defects in the National Birth Defects Prevention Study.
BACKGROUND
Although thyroid disorders are present in approximately 3% of pregnant women, little is known about the association between maternal thyroid disease and birth defects.


METHODS
We assessed the association between maternal thyroid disease, thyroid medication use, and 38 types of birth defects among 14,067 cases and 5875 controls in the National Birth Defects Prevention Study, a multisite, population-based, case-control study. Infants in this study were born between October 1997 and December 2004. Information on exposures including maternal diseases and use of medications was collected by telephone interview.


RESULTS
We found statistically significant associations between maternal thyroid disease and left ventricular outflow tract obstruction heart defects (1.5; 95% CI, 1.0-2.3), hydrocephaly (2.9; 95% CI, 1.6-5.2), hypospadias (1.6; 95% CI, 1.0-2.5), and isolated anorectal atresia (2.4; 95% CI, 1.2-4.6). Estimates for the association between periconceptional use of thyroxine and specific types of birth defects were similar to estimates for any thyroid disease. Given that antithyroid medication use was rare, we could not adequately assess risks for their use for most case groups.


CONCLUSIONS
Our results are consistent with the positive associations between maternal thyroid disease or thyroid medication use and both hydrocephaly and hypospadias observed in some previous studies. New associations with left ventricular outflow tract obstruction heart defects and anorectal atresia may be chance findings.
Browne
Marilyn L
ML
Congenital Malformations Registry, New York State Department of Health, Troy, New York, USA. mlb10@health.state.ny.us
Rasmussen
Sonja A
SA
Hoyt
Adrienne T
AT
Waller
D Kim
DK
Druschel
Charlotte M
CM
Caton
Alissa R
AR
Canfield
Mark A
MA
Lin
Angela E
AE
Carmichael
Suzan L
SL
Romitti
Paul A
PA
D000015:Abnormalities, Multiple / Q000453:epidemiology; D000293:Adolescent; D000328:Adult; D013956:Antithyroid Agents / Q000627:therapeutic use*; D016022:Case-Control Studies; D002648:Child; D000013:Congenital Abnormalities / Q000453:epidemiology* / Q000517:prevention & control; D005260:Female; D006801:Humans; D018811:Maternal Exposure; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology* / Q000517:prevention & control; D011297:Prenatal Exposure Delayed Effects; D013959:Thyroid Diseases / Q000150:complications* / Q000188:drug therapy
D013956:Antithyroid Agents