Made to Miscarry

Thyroid Autoimmunity
and Miscarriage

By Teri Brown

Penny Wade of Sherwood, Ore., is an intelligent, educated mother of one. After having her first child, Wade had difficulty conceiving another. When she did conceive, she couldn't carry the baby to term. She also has hypothyroidism, a disease associated with thyroid antibodies.

In fact, one study conducted by the Endocrine Society of more than 200 women with fertility issues found that those who tested positive for thyroid antibodies prior to receiving fertility treatments were at an increased risk for miscarriage.

"I had no idea that there might have been a connection," says Wade. "Had I known, I might have made other reproductive choices or at least went into the assisted reproductive treatments with more information."

Dr. Kris Poppe, a reproductive endocrinologist from Brussels, Belgium, and one of the authors of the study, found thyroid antibodies in 14 percent of the women in the study. Yet, the miscarriage rate for the women who did conceive with fertility treatments was more than 50 percent, compared with only 23 percent in the women negative for thyroid antibodies.

According to Dr. Poppe, thyroid autoimmunity is the presence of increased antibodies (detectable in the blood) against an enzyme of the thyroid needed to maintain a normal level of thyroid hormones. "Indeed, the women have the same pregnancy rate, but those with thyroid autoimmunity have a double risk of miscarriage," says Dr. Poppe.

Dr. Ken Gelman, a reproductive endocrinologist and an assistant clinical professor at the University of Miami School of Medicine, says that thyroid autoimmunity is fairly common. "Approximately 15 percent of women may have antibodies directed against their thyroid," he says.

Just because you have thyroid antibodies doesn't mean you will show evidence of thyroid diseases. Hypothyroidism is a thyroid disease where the body produces too little of the thyroid hormone. With hyperthyroidism, the body produces too much of the hormone. Both can be controlled with medication, but it is still unknown as to whether or not medication impacts women having multiple miscarriages due to thyroid autoimmunity.

Want to see more?

• Pregnancy After Loss: Are You Ready to Try Again?
• You've Had a Miscarriage: What Now?
• When a Miscarriage Isn't Nature's Way
• Talk about it!