Pregnant Women With Lupus and Thyroid Disease at Increased Risk for Preterm Deliveries

Deborah Brauser

September 30, 2009

September 30, 2009 (Palm Beach, Florida) — Women with systematic lupus erythematosus (SLE) who become pregnant are at risk for thyroiditis, according to a retrospective cohort study presented here at the American Thyroid Association (ATA) 80th Annual Meeting.

In addition, the study found that women with both SLE and thyroid disease have a significantly increased risk of having a preterm delivery.

"Autoimmune thyroid disease is common in pregnancy and is associated with miscarriage, preterm delivery, and decreased IQ in offspring," said lead investigator Alex Stagnaro-Green, MD, from the Department of Medicine, Obstetrics and Gynecology at Touro University College of Medicine in Hackensack, New Jersey, during his presentation. "Lupus, which is another autoimmune disorder, is also associated with miscarriage and preterm delivery."

The objectives of this study were to determine the incidence of thyroid disease in women with SLE during pregnancy and postpartum, and to evaluate the impact of thyroid disease on pregnancy outcomes.

The investigators retrospectively evaluated data from 63 women who took part in the Hopkins Lupus Cohort, an ongoing observational study. These patients had sera frozen during pregnancy and/or the first year postpartum. All specimens were tested for thyroid-stimulating hormone (TSH) and thyroid antibodies.

In addition, demographics, laboratory data, and pregnancy outcomes were available for all Hopkins Lupus Cohort participants.

For this study, postpartum thyroiditis was defined as "a TSH below 0.3 μU/mL or above 4.0 μU/mL in the first postpartum year in women who were euthyroid during pregnancy." Preterm delivery was defined as delivery prior to 37 weeks of gestation.

Thyroid Disease Found in 38% of the Women

At the first prenatal visit, 24% of the women (n = 15) were found to be positive for thyroid antibodies; 13% of those (n = 8) already had thyroid disease and were taking levothyroxine prior to becoming pregnant, and the other 11% (n = 7) were diagnosed from their first pregnancy sample.

Of the 43 remaining women who had postpartum samples available for analysis, 14% (n = 6) developed postpartum thyroiditis.

"So in this study, we basically found that 1 out of every 3 pregnant women with lupus had thyroid disease before, during, or after pregnancy," reported Dr. Stagnaro-Green.

Preterm Delivery Risk Increased

A total of 18% of the women with SLE and no thyroid disease experienced preterm deliveries; the number of preterm deliveries increased to 67% for those with both conditions (= .002).

"This was an important finding," said Dr. Stagnaro-Green. "In the normal population, there's a 12% chance of preterm delivery. We found that that went up to 18% if the women had lupus without thyroid disease, but increased almost 4-fold for the women with both lupus and thyroid disease."

"That's a real concern because preterm delivery is one of the leading causes of neonatal morbidity and mortality in the United States. It has been increasing and it's one of the things that the surgeon general is trying to decrease in the Healthy People 2010 [report]," he explained.

Finally, there were no differences in SLE disease-related activity between women with thyroid disease and those without.

Screening Recommended Prior to Pregnancy

"It can be concluded that women with lupus have a markedly increased incidence of autoimmune thyroid disease," said Dr. Stagnaro-Green. "Women with lupus and thyroid disease have a dramatically increased risk of having a preterm delivery. Therefore, it is recommended that all women with lupus be checked for thyroid disease prior to pregnancy."

"I think the next step is a public health issue to get the message out," he added. "There are a lot of concerns for pregnant women right now, and a lot of really exciting but disconcerting data that have been coming out."

"The bottom line is if a pregnant woman is at high risk for thyroid disease, she needs to be screened and treated. We need to have a nationwide discussion on whether or not all pregnant women should be screened," said Dr. Stagnaro-Green.

Striking Results

Kathryn G. Schuff, MD, associate professor of medicine and associate endocrinology fellowship program director at Oregon Health and Sciences University in Portland, and clinical cochair of the ATA Program Committee, called the results from this trial "exciting." Dr. Schuff was not involved with the study.

"The really striking part of this study, in addition to the fact that a third of the women with lupus had thyroid disease, is that they went in and looked at pregnancy outcomes and found a huge increase in the incidence of preterm delivery in women who had both lupus and thyroid disease," Dr. Schuff told Medscape Diabetes & Endocrinology.

"We've always known that outcomes in pregnancy were poor for women with lupus," she continued. "But I think the intriguing thing about these results is [that] a lot of those adverse outcomes [might] actually [be] related to unrecognized autoimmune thyroid disease, and that that's actually the culprit in these adverse pregnancy outcomes."

Dr. Schuff concluded: "I'm excited to see these results and [want] to really raise the question and raise awareness among OB/GYN doctors that patients with any kind of autoimmune disease really should be evaluated for thyroid disease during the course of the pregnancy. And the doctors should be alert to the fact that thyroid disease may be underlying some of the adverse outcomes that we see with other autoimmune diseases."

Dr. Stagnaro-Green and Dr. Schuff have disclosed no relevant financial relationships.

American Thyroid Association (ATA) 80th Annual Meeting: Poster 107. Presented September 25, 2009.

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