Mother with Arthritis

The prospect of pregnancy can be daunting for women with inflammatory arthritis. Not only can disease flares occur, but a host of medications — including the commonly prescribed methotrexate — are off-limits because of concerns about birth defects and complications. There’s also a worrisome information gap on the effects of many medications during pregnancy, since pregnant women are usually excluded from clinical trials.

One type of medication, tumor necrosis factor inhibitors (TNF inhibitors), is increasingly used during pregnancy after animal studies did not show a risk to the developing fetus. But that left open the question of whether the drugs, as they suppress the immune system in expectant moms in order to manage their disease, might also lessen immune response in their newborns, leaving babies more vulnerable to infection after they’re born.

Last year, researchers at McGill University in Canada used a large health database in the United States to address that question for women with rheumatoid arthritis (RA). They found that that there was no excess risk for babies exposed to anti-TNF biologics compared to offspring of women with RA who didn’t take these drugs and to women without RA.

This year, the group is back with a similar analysis of serious infections in babies exposed to non-TNFi biologics, such as abatacept (Orencia), rituximab (Rituxan), tocilizumab (Actemra), ustekinumab (Stelara), and vedolizumab (ENTYVIO). Like TNFis, non-TNFi biologics can cross the placenta, leading to medication exposure than can equal or surpass that of the expectant woman. They also evaluated tofacitinib (Xeljanz), a small-molecule drug that may also cross the placenta (although that has not been confirmed).

The new study was presented at the 2019 American College of Rheumatology/Association of Rheumatology Health Professionals Annual Meeting in Atlanta.

“Our project innovates by using the largest cohort of pregnant women with chronic inflammatory diseases ever assembled to address drug safety in pregnant women, who are regularly excluded from clinical trials,” lead author Evelyne Vinet, MD, PhD, told the American College of Rheumatology in a press release.

The investigators tallied infections that occurred in 16,490 babies before their first birthdays that were serious enough to require hospitalization. All of their mothers had been diagnosed with an inflammatory disease, such as rheumatoid arthritis, ankylosing spondylitis, psoriasis, psoriatic arthritis, or inflammatory bowel disease. During pregnancy, 105 of the mothers took tofacitinib or non-TNFi biologics and 1,611 took TNFis. Infections in those children were compared to those in 164,553 babies born to unaffected mothers matched for age, year of delivery, and state of residence.

The researchers found just two cases of serious infections in exposed children, one whose mother received tofacitinib and one whose mother received abatacept. Overall, the proportion of serious infections in offspring of mothers with inflammatory disease was: 1.9% in those exposed to tofacitinib or non-TNFi biologics; 2.3% in those exposed to TNFis; and 2.1% of those exposed to neither type of drug. In comparison, the percent of serious infections in children born to unaffected mothers was 1.6%.

“Our data will help guide counseling and management of pregnant women with inflammatory arthritis that require non-TNFi biologics and tofacitinib during pregnancy,” says Dr. Vinet. Still, she considers this analysis to be just the first step in understanding the effect of these drugs during pregnancy.

“We need more data to confirm safety, particularly regarding other pregnancy outcomes. It is imperative that we further study this issue to provide firm evidence to guide treatment decisions prior to conception and throughout pregnancy,” she says.

You Can Participate in Arthritis Research Too

If you are diagnosed with arthritis or another musculoskeletal condition, we encourage you to participate in future studies by joining CreakyJoints’ patient research registry, ArthritisPower. ArthritisPower is the first-ever patient-led, patient-centered research registry for joint, bone, and inflammatory skin conditions. Learn more and sign up here.

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