The Effect of Low-Dose Aspirin on Disease Activity in Pregnant Individuals With Inflammatory Bowel Disease

Low-dose aspirin (LDA) is recommended for pregnant individuals at elevated risk for hypertensive disorders of pregnancy (HDP). However, regular aspirin use may raise concerns of increased disease activity in patients with inflammatory bowel disease (IBD). We aimed to evaluate the prevalence of LDA use in pregnant IBD patients and the effect of LDA on IBD disease activity.

Included were individuals with IBD and pregnancy followed by maternal fetal medicine between January 1, 2013, and December 31, 2022. LDA use was ascertained from medication lists during pregnancy. Primary outcome was IBD flare during pregnancy or 6-month postpartum, defined as IBD-related hospitalization or surgery, new therapy initiation, elevated fecal calprotectin, or new active endoscopic disease.

Among 320 pregnancies in women with IBD (232 patients), 90 (28%) were prescribed aspirin during pregnancy. The percentage of women with IBD flare during pregnancy or postpartum was similar among those who were and were not prescribed aspirin (20% vs 26%, P = 0.36). Individuals on aspirin were older (35 vs 34 median years), more likely to have preterm birth (21% vs 14%), higher parity (2 vs 1), and cesarean delivery (50% vs 27%) than individuals not on LDA (all P < 0.01). Both groups had similar rates of HDP, although individuals on LDA had higher rates of preeclampsia (10% vs 4.3%, P = 0.10).

Approximately one-third of patients with IBD cared for in a maternal fetal medicine practice were prescribed LDA during pregnancy. The use of aspirin among pregnant patients with IBD was not associated with an increased risk of disease activity.