Anti-TNF-α Use During the Third Trimester of Pregnancy in Women with Moderate-severe Inflammatory Bowel Disease and the Risk of Preterm Birth and Low Birth Weight

BACKGROUND: Little knowledge exists about the association between anti-tumor necrosis factor-alpha (anti-TNF-α) therapy for inflammatory bowel disease during late pregnancy and adverse birth outcomes. We aimed to examine whether treatment with anti-TNF-α during the third trimester affected preterm birth and low birth weight (LBW), compared with women who discontinued anti-TNF-α therapy before the third trimester. METHODS: We identified a nationwide cohort of 219 women treated with anti-TNF-α during the pregnancy period and reviewed the medical records to extract clinical details. The exposed cohort (n = 113, 51.6%) constituted pregnancies exposed to anti-TNF-α during the third trimester, and the unexposed cohort (n = 106, 48.4%) constituted pregnancies with no anti-TNF-α during the third trimester. The association between anti-TNF-α therapy in the third trimester and adverse birth outcomes was studied (1) in those women who had clinical disease activity during pregnancy and (2) in women who had no clinical disease activity during pregnancy. RESULTS: In women with disease activity, treated with anti-TNF-α during the third trimester, we found an adjusted odds ratio of 2.23 (95% confidence interval [CI], 0.80-6.20) for preterm birth and 1.16 (95% CI, 0.26-5.23) for LBW. Among women without disease activity, treated with anti-TNF-α therapy during the third trimester, we found an adjusted odds ratio of 3.36 (95% CI, 0.31-36.46) for preterm birth and 0.86 (95% CI, 0.05-14.95) for LBW. CONCLUSIONS: For anti-TNF-α therapy in the third trimester, we found no statistically significant increased risk of either LBW or preterm birth.