Trends in common laboratory markers during pregnancy in women with IBD in clinical remission

This is the authors' abstract. We don't add key points for this paper.

BACKGROUND: Physiologic pregnancy changes can alter commonly monitored laboratory values and mimic active inflammatory bowel disease (IBD), complicating prenatal disease monitoring. Biomarker trajectories in women with IBD in remission are not well established. We aimed to characterize trimester-specific changes in key biomarkers among women with IBD in remission before and throughout pregnancy. METHODS: We performed a retrospective review of pregnant women with IBD in remission enrolled in a prospective preconception/pregnancy registry. Eligible patients had laboratory data from the preconception period and at least 1 trimester (first trimester [T1], second trimester [T2], or third trimester [T3]). Parameters included complete blood counts, albumin, C-reactive protein, erythrocyte sedimentation rate (ESR), iron studies, and fecal calprotectin (FC). Changes from preconception were assessed using Wilcoxon signed rank tests and McNemar's test when applicable. RESULTS: Sixty-eight pregnancies from 61 women were included (68.9% Crohn's disease, 27.9% ulcerative colitis; median age 33 years; 83.8% on biologics). Compared with preconception, ESR and white blood cell count rose across trimesters (ESR PT2T3 < .001; white blood cell PT1-T3 < .001). Hemoglobin, hematocrit, platelets, and albumin declined significantly, particularly in T2/T3 (all P ≤ .008). C-reactive protein rose during all trimesters (PT1 = .003; PT2, T3 < .001), whereas FC remained stable and within normal range throughout pregnancy (all P > .05). Most biomarkers trended toward baseline postpartum. CONCLUSIONS: In pregnant women with IBD in remission, most laboratory changes appear physiologic, requiring cautious interpretation. FC was the only stable biomarker throughout pregnancy and remains the most reliable marker of inflammation during this period. These trimester-specific data may improve interpretation of biomarkers in pregnant patients with IBD.