Study finds biologic use drops during pregnancy in autoimmune patients

Study finds biologic use drops during pregnancy in autoimmune patients | Image Credit: © Subbotina Anna - © Subbotina Anna - stock.adobe.com.

Pregnancy is linked to a decrease in biologics use among patients with autoimmune disease, which only partially rebounds after delivery, according to a recent study published in JAMA Network Open.

Challenges of managing autoimmune disease

An autoimmune condition is reported in 4.1% of pregnant patients, leading to difficulty managing because of the need to optimize risks and benefits for the mother and fetus. However, these diseases have been linked to preterm delivery, small for gestational age infant, and stillbirth.² Biologic anti-inflammatory agents may be recommended for treatment.¹

“Despite the increase in biologic use among pregnant patients, evidence supporting the safe use of biologics during pregnancy is limited,” wrote investigators. Therefore, the retrospective cohort study was conducted to determine associations of autoimmune condition factors and treatment decisions during pregnancy.

Evaluating autoimmune conditions

Data was obtained from the Merative MarketScan Commercial Claims Research Databases, which include patient-level data for privately insured US patients. Diagnoses and procedure data, alongside medication use, was available in these databases.

Women who conceived from January 1, 2011, to December 31, 2021, with an autoimmune condition were included in the analysis. Additional eligibility criteria included at least 6 months of continuous health care coverage before conception and at least 6 months of coverage after birth.

Relevant autoimmune conditions included Crohn's disease, rheumatoid arthritis, ulcerative colitis, systemic lupus erythematosus, ankylosing spondylitis, psoriasis or psoriatic arthritis, and multiple sclerosis. Multiple conditions were defined by having more than 1 of these conditions documented.

Biologic use measurement

Biologic use during the 180-day preconception period was required in patients with a documented autoimmune condition, with the date of use assumed to be the date of dispensing or visit. The rate of pregnancies with biologic use after conception was reported as the primary outcome, determined by a dispensing or administrative claim in the relevant gestation period.

Measurements of biologic use were performed for the preconception, first trimester, second trimester, third trimester, and postpartum periods. Additional assessments were performed based on therapeutic category and temporal trends.

Condition prevalence and pregnancy outcomes

There were 6131 pregnant women with biologic use included in the analysis, aged a median 32 years. Crohn's disease and rheumatoid arthritis were the most common conditions in this population, with rates of 25.6% and 24.1%, respectively. Additionally, 22.6% of patients had more than 1 concurrent autoimmune diagnosis,

A live birth occurred in 70.8% of women, spontaneous abortion in 21.5%, and induced abortion in 5.2%. Additionally, 25.6% of patients had a history of systemic glucocorticoid use 6 months before conception.

Trends in biologic use

One or more instances of biologic use during the conception period were reported in 71.6% of patients. Additionally, reinitiation of biologic use after pregnancy ended was reported in 52.8% of those with no biologic use during pregnancy.

Biologic use rates among pregnancies with live birth outcomes were 68.6%, 58.8%, and 48.6% in the first, second, and third trimester, respectively, highlighting a decline throughout gestation. While the rate rose to 77.1% during the postpartum period, this rate remained lower than before conception.

Patients with multiple sclerosis reported the most significant drop, with first-trimester, second-trimester, and third-trimester rates of 29.7%, 10.3%, and 7.3%, respectively. This was followed by systemic lupus erythematosus, with rates of 32.6%, 10.9%, and 8.7%, respectively. In comparison, high retention was reported in patients with ulcerative colitis and Crohn's disease.

Trends and implications

Biologic use had an increasing secular trend between 2011 and 2021, with an odds ratio of 2.55. An increasing trend of at least 1 case of biologic use during pregnancy was also reported, from 95.7% in 2011 to 65.7% in 2021. Overall, the results highlighted variations in biologic use during pregnancy based on the patients’ autoimmune conditions.

“Future condition-specific studies evaluating safety and efficacy of biologics are needed to enhance our understanding of the risks and benefits of biologic use for both mother and infant,” wrote investigators.

References

1. Ewig CLY, Wang Y, Smolinski NE, Thai TN, Rasmussen SA, Winterstein AG. Use of biologics during pregnancy among patients with autoimmune conditions. JAMA Netw Open. 2025;8(5):e2510504. doi:10.1001/jamanetworkopen.2025.10504
2. Bröms G, Granath F, Linder M, Stephansson O, Elmberg M, Kieler H. Birth outcomes in women with inflammatory bowel disease: effects of disease activity and drug exposure. Inflamm Bowel Dis. 2014;20(6):1091-8. doi:10.1097/MIB.0000000000000060