S17 Therapeutic Drug Monitoring of the Biosimilar (AMJEVITA™, Adalimumab-atto) Using Labcorp Adalimumab Assay for Drug Level and Anti-Drug Antibodies

Background: There are limited studies assessing the impact of pediatric-onset in fl ammatory bowel disease (IBD) on infant and pregnancy outcomes. Low birth weight and preterm birth are known pregnancy complications in IBD patients with active disease. Therefore, this study sought to evaluate pregnancy outcomes in patients with pediatric-onset versus adult-onset Crohn ’ s disease (CD), particularly with regard to intrauterine growth and prematurity delivery. Methods: In this single center, retrospective comparative cohort study, patients with pediatric-onset (diagnosed , 18 years old) and adult-onset CD (diagnosed $ 18 years old) who had documented prenatal care between 2012-2023 were identi fi ed. Patients were excluded for following at outside institutions for primary IBD care. We compared co-primary outcomes (gestational age and size), and secondary outcomes (assisted reproduction usage, mode of delivery, and neonatal intensive care unit (NICU) stay), between the two groups. Data was obtained from an electronic medical record via natural language processing and con fi rmed with manual veri fi cation. Categorical variables were analyzed using chi-squared test or Fisher exact test when appropriate; continuous variables were assessed with t-test if normally distributed. Statistical signi fi cance was determined by p value , 0.05. Results: A total of 208 infants were delivered, 119 to pediatric-onset CD and eighty-nine to adult-onset CD mothers. There was no signi fi cant di ff erence with regard to race between the groups. The mother ’ s age at delivery was signi fi cantly lower in pediatric-onset CD patients (median [IQR]: 30.2 [26.3, 34.5] vs 32.5 [29.8, 35.3] years, p 5 0.0006). There was a numerically