1/15/2026
New research published in ACR Open Rheumatology suggests that using TNF inhibitors during pregnancy does not increase the risk of serious infections.
Researchers used a large U.S. health insurance database called MarketScan to study pregnant people with chronic inflammatory diseases, including rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, psoriasis, and inflammatory bowel disease. The study included women ages 15 to 45 who were pregnant between 2011 and 2021 and who had continuous insurance coverage before and during pregnancy.
In total, the researchers followed 62,813 women, accounting for 70,529 pregnancies and 69,412 births. About 7% of these women used a TNF inhibitor (TNFi) during pregnancy, and about 5% used a TNFi in the postpartum period. TNFi included commonly prescribed medications such as infliximab, adalimumab, etanercept, certolizumab, and golimumab.
Rather than classifying people as simply “exposed” or “not exposed,” the study tracked TNFi use over time. This allowed researchers to account for changes in treatment during pregnancy and after birth. The main outcome they studied was serious infections that required hospitalization, measured during pregnancy and up to 90 days after delivery. The analysis adjusted for many other factors that could influence infection risk, including age, other medical conditions, medication use, and markers of disease severity.
Overall, the study found no statistically significant increase in the risk of serious infections among pregnant or postpartum women who used TNFi compared with those who did not. Although infection rates were numerically higher among TNFi users—during both pregnancy and the postpartum period—these differences were not statistically significant, meaning the findings were also consistent with no increased risk.
The types of serious infections observed were similar between groups and included pregnancy-related infections, urinary tract infections, viral or systemic infections, and postpartum infections related to delivery. No fatal infections were reported, and the researchers found no clear evidence linking increased infection risk to any specific TNFi, though they noted that uncertainty remains and further research is warranted.
The researchers point out several limitations of the study. Prescription records reflect medications dispensed, not necessarily taken, and the database lacked direct measures of disease activity, such as lab results. Although the analysis adjusted for many related factors, some influences, such as smoking, body weight, or socioeconomic status, could not be fully accounted for. Pregnancy timing was also estimated rather than based on exact clinical dates, and people using TNFi may have been monitored more closely, potentially increasing hospital admissions for infections.
Despite the limitations, this is the largest real-world study to date examining TNFi use during pregnancy and the postpartum period. By tracking medication use over time and including the weeks after delivery, the study helps fill important gaps in earlier research and provides reassurance about use of TNF inhibitors during pregnancy.
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