Thyroid Hormone Imbalance Can Harm Fetus
Thursday August 12, 2004
Researchers have found further evidence that being hyperthyroid or hypothyroid during pregnancy is a risk to the fetus. In research published in the Journal of the American Medical Association, researchers cautioned doctors to be careful when giving thyroid hormone replacement to pregnant women.
On the one hand, hypothyroidism is a known factor that can lead to congenital abnormalities in the child, slow or retard growth, impair IQ, and can endanger the pregnancy itself with an increased risk of miscarriage and stillbirth. One of the key concerns is getting enough thyroid hormone during pregnancy, and one study recent reported that a hypothyroid woman who becomes pregnant should immediately increase her dose by 29 percent.
At the same time, hyperthyroidism may also be a risk to the fetus, but this new research studied family that has a genetic predisposition to hyperthyroidism. Some members of the family had a gene that protects against effects of the hyperthyroidism. In the research, the women who did not have the gene were more likely to miscarry. Where the mother had the gene but the baby did not, there was triple the risk of miscarriage.
While the researchers have concluded that too much thyroid hormone is a danger, this study looked at people who were genetically hyperthyroid, not hyperthyroid due to excess thyroid hormone replacement. It appears that while the objective of a physician managing a woman during pregnancy should be to provide sufficient thyroid hormone replacement throughout the entire pregnancy, further study is needed to determine if suppressive doses of thyroid hormone -- that make the mother hyperthyroid -- are a risk to the fetus.
FOR MORE INFORMATION
On the one hand, hypothyroidism is a known factor that can lead to congenital abnormalities in the child, slow or retard growth, impair IQ, and can endanger the pregnancy itself with an increased risk of miscarriage and stillbirth. One of the key concerns is getting enough thyroid hormone during pregnancy, and one study recent reported that a hypothyroid woman who becomes pregnant should immediately increase her dose by 29 percent.
At the same time, hyperthyroidism may also be a risk to the fetus, but this new research studied family that has a genetic predisposition to hyperthyroidism. Some members of the family had a gene that protects against effects of the hyperthyroidism. In the research, the women who did not have the gene were more likely to miscarry. Where the mother had the gene but the baby did not, there was triple the risk of miscarriage.
While the researchers have concluded that too much thyroid hormone is a danger, this study looked at people who were genetically hyperthyroid, not hyperthyroid due to excess thyroid hormone replacement. It appears that while the objective of a physician managing a woman during pregnancy should be to provide sufficient thyroid hormone replacement throughout the entire pregnancy, further study is needed to determine if suppressive doses of thyroid hormone -- that make the mother hyperthyroid -- are a risk to the fetus.
FOR MORE INFORMATION
- Research Source: Anselmo J, et. al. "Fetal Loss Associated With Excess Thyroid Hormone Exposure." JAMA. 2004 Aug 11;292(6):691-695.
- Pregnant with Hypothyroidism? Increase Your Medication!!! -- Researchers Find Thyroid Hormone Needs Increase During Early Pregnancy
- Fertility, Pregnancy & Thyroid Disease Information Center
- Thyroid Guide to Pregnancy, Fertility & Breastfeeding Success
Comments
No comments yet. Leave a Comment