Biologic Drug Use During Pregnancy Varies Dramatically by Autoimmune Condition

Managing autoimmune diseases during pregnancy presents a complex challenge, as clinicians must balance the risks of active disease against potential medication effects on the developing fetus. This large-scale study provides the first comprehensive picture of how biologic medications are actually used across different autoimmune conditions during pregnancy.

Researchers analyzed insurance claims data from over 6,000 pregnant women with autoimmune conditions who were using biologic medications before conception. The study tracked seven major conditions: Crohn's disease, ulcerative colitis, rheumatoid arthritis, psoriasis/psoriatic arthritis, ankylosing spondylitis, lupus, and multiple sclerosis.

The results revealed striking differences in treatment patterns. Overall, 71.6% of women continued biologics at least once during pregnancy, but this varied dramatically by condition. Women with inflammatory bowel diseases (Crohn's and ulcerative colitis) were far more likely to continue treatment, while those with skin conditions like psoriasis were more likely to discontinue. Biologic use declined throughout pregnancy, dropping from 68.6% in the first trimester to 48.6% in the third trimester.

These patterns suggest that perceived risks and benefits vary significantly across conditions. IBD patients may continue treatment because active disease poses serious risks to both mother and baby, including preterm delivery and low birth weight. In contrast, psoriasis patients may discontinue because the condition is less immediately life-threatening during pregnancy.

The study highlights the urgent need for condition-specific pregnancy guidelines and more robust safety data for newer biologic medications. Current recommendations are often inconsistent, leaving patients and providers to make difficult decisions with limited evidence.