Thyroid disease is the second most common hormone disorder
affecting women of childbearing age. Both overactive thyroid, most
often the result of Graves disease, and underactive thyroid are
linked with adverse pregnancy outcomes.
Craniosynostosis occurs when the sutures (fibers) between the
bones in an infant’s skull close too early. If not corrected with
surgery, the condition leads to a deformed head shape, stunted brain
growth, and increased pressure on the brain. This condition occurs
in about 1 in 2,000 births.
Using data from a large national study, researchers looked at the
link between maternal thyroid disease and craniosynostosis.
Researchers used data from the National Birth Defects Prevention
Study (NBDPS) to analyze the link between maternal thyroid disease
and craniosynostosis. The NBDPS is an ongoing, population-based,
case-control study in nine states of genetic and environmental risk
factors for major birth defects.
The infants in the study had craniosynostosis that was confirmed
by radiographic imaging. The mothers were identified as having
thyroid disease if they reported having a thyroid disorder or taking
medicine to treat a thyroid disorder during pregnancy.
Important findings from this study include:
- Mothers of infants with craniosynostosis were more than
twice as likely to report thyroid disease (most likely Graves
disease) or its treatment than were mothers of infants without
the condition. This finding remained unchanged after researchers
adjusted for other factors, including mother’s age, that might
also affect risk.
- Most infants with craniosynostosis (89%) had a single suture
involved. Most (90%) had no other major, unrelated birth
defects. The sagittal suture (running from the front to the back
of the skull) was most commonly involved.
- These findings are similar to those of past case reports of
craniosynostosis after exposure to increased levels of thyroid
hormone. Given how often maternal thyroid disease occurs, this
link warrants more research.
Rasmussen SA, Yazdy MM, Carmichael SL, Jamieson DJ, Canfield MA,
Honein MA, for the National Birth Defects Prevention Study. Maternal
thyroid disease as a risk factor for craniosynostosis. Obstet
Gynecol. 2007;110(2):369–77.
Date:
March 11, 2009
Content source: National Center on Birth Defects and Developmental
Disabilities
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