Preliminary review finds no association between anti-TNF-alpha use and adverse pregnancy outcomes

February 19, 2005

Analyses of limited data collected by the Organization of Teratology Information Services (OTIS) suggest there is no increased risk of major malformations or spontaneous abortions in women who received treatment with an anti-tumor necrosis factor-alpha medication early during pregnancy, reports Christina Chambers, Ph.D.

Analyses of limited data collected by the Organization of Teratology Information Services (OTIS) suggest there is no increased risk of major malformations or spontaneous abortions in women who received treatment with an anti-tumor necrosis factor-alpha medication early during pregnancy, reports Christina Chambers, Ph.D.

The analyses compared outcomes in 33 women with rheumatoid arthritis (RA) and first-trimester exposure to etanercept (n=29) or infliximab (n=4) against two control groups - one consisting of 86 women with RA who were not treated with an anti-TNF-alpha medication and 51 non-diseased controls who had neither RA nor exposure to an anti-TNF-alpha agent.

The rate of spontaneous abortion/stillbirth/blighted ovum among the women exposed to etanercept or infliximab (9.1 percent) was not significantly different from that occurring in the RA controls (8.1 percent) or non-diseased controls (3.9 percent), and rates of major structural defects were also similar among the three groups (3.0 to 3.9 percent).

However, mean length of gestation and mean birth weight were both significantly lower in the two RA groups relative to the non-diseased controls. That finding suggests a contributing role of the underlying condition rather than the medication, noted Dr. Chambers.

"Increasing numbers of women of reproductive age may benefit from treatment with the anti-TNF-alpha medications, but these agents have not been well-studied with regard to use in pregnancy.

Adequate pregnancy safety data are critical to making appropriate treatment decisions for these women, and we will continue to recruit subjects for this cohort over the next five years to better characterize the safety of these medications when used in pregnancy," says Dr. Chambers, assistant professor of pediatrics, University of California at San Diego.