Tofacitinib in Pregnancy: Assessing Pregnancy and Infant Outcomes, Cord Blood, and Breast Milk Concentrations.

Janus kinase (JAK) inhibitors are effective anti-inflammatory agents for treatment of ulcerative colitis (UC).1 According to drug regulatory agencies and international guidelines, JAK inhibitors should be avoided during pregnancy and lactation.2-4 The existing evidence on safety of JAK inhibitors during pregnancy is scarce and almost exclusively limited to tofacitinib.4-7.

Infant Ustekinumab Clearance, Risk of Infection, and Development After Exposure During Pregnancy.

BACKGROUND: Evidence on ustekinumab safety in pregnancy is gradually expanding, but its clearance in the postnatal period is unknown. The aim of this study was to investigate ustekinumab concentrations in umbilical cord blood and rates of clearance after birth, as well as how these correlate with maternal drug concentrations, risk of infection, and developmental milestones during the first year of life. METHODS: Pregnant women with inflammatory bowel disease were prospectively recruited from 19 hospitals in Denmark and the Netherlands between 2018 and 2022. Infant infections leading to hospitalization/antibiotics and developmental milestones were assessed. Serum ustekinumab concentrations were measured at delivery and specific time points. Nonlinear regression analysis was applied to estimate clearance. RESULTS: In 78 live-born infants from 76 pregnancies, we observed a low risk of adverse pregnancy outcomes and normal developmental milestones. At birth, the median infant-mother ustekinumab ratio was 2.18 (95% confidence interval, 1.69-2.81). Mean time to infant clearance was 6.7 months (95% confidence interval, 6.1-7.3 months). One in 4 infants at 6 months had an extremely low median concentration of 0.015 µg/mL (range 0.005-0.12 µg/mL). No variation in median ustekinumab concentration was noted between infants with (2.8 [range 0.4-6.9] µg/mL) and without (3.1 [range 0.7-11.0] µg/mL) infections during the first year of life (P = .41). CONCLUSIONS: No adverse signals after intrauterine exposure to ustekinumab were observed with respect to pregnancy outcome, infections, or developmental milestones during the first year of life. Infant ustekinumab concentration was not associated with risk of infections. With the ustekinumab clearance profile, live attenuated vaccination from 6 months of age seems of low risk.

Concentrations of Adalimumab and Infliximab in Mothers and Newborns, and Effects on Infection.

BACKGROUND & AIMS: Little is known about in utero exposure to and postnatal clearance of anti-tumor necrosis factor (anti-TNF) agents in neonates. We investigated the concentrations of adalimumab and infliximab in umbilical cord blood of newborns and rates of clearance after birth, and how these correlated with drug concentrations in mothers at birth and risk of infection during the first year of life. METHODS: We performed a prospective study of 80 pregnant women with inflammatory bowel diseases at tertiary hospitals in Denmark, Australia, and New Zealand from March 2012 through November 2014: 36 received adalimumab and 44 received infliximab; 39 received concomitant thiopurines during pregnancy. Data were collected from medical records on disease activity and treatment before, during, and after pregnancy. Concentrations of anti-TNF agents were measured in blood samples from women at delivery and in umbilical cords, and in infants for every 3 months until the drug was no longer detected. RESULTS: The time from last exposure to anti-TNF agent during pregnancy correlated inversely with the concentration of the drugs in the umbilical cord (adalimumab: r = -0.64, P = .0003; infliximab: r = -0.77, P < .0001) and in mothers at time of birth (adalimumab, r = -0.80; infliximab, r = -0.80; P < .0001 for both). The median ratio of infant:mother drug concentration at birth was 1.21 for adalimumab (95% confidence interval [CI], 0.94-1.49) and 1.97 for infliximab (95% CI, 1.50-2.43). The mean time to drug clearance in infants was 4.0 months for adalimumab (95% CI, 2.9-5.0) and 7.3 months for infliximab (95% CI, 6.2-8.3; P < .0001). Drugs were not detected in infants after 12 months of age. Bacterial infections developed in 4 infants (5%) and viral infections developed in 16 (20%), all with benign courses. The relative risk for infection was 2.7 in infants whose mothers received the combination of an anti-TNF agent and thiopurine, compared with anti-TNF monotherapy (95% CI, 1.09-6.78; P = .02). CONCLUSIONS: In a prospective study of infants born to mothers who received anti-TNF agents during pregnancy, we detected the drugs until 12 months of age. There was an inverse correlation between the time from last exposure during pregnancy and drug concentration in the umbilical cord. Infliximab was cleared more slowly than adalimumab from the infants. The combination of an anti-TNF agent and thiopurine therapy during pregnancy increased the relative risk for infant infections almost 3-fold compared with anti-TNF monotherapy. Live vaccines therefore should be avoided for up to 1 year unless drug clearance is documented, and pregnant women should be educated on the risks of anti-TNF use.

Adherence and quality of care in IBD.

OBJECTIVE: In inflammatory bowel disease (IBD), adherence to both medical treatment and other aspects of care has a substantial impact on the course of the disease. Most studies of medical adherence have reported that 30-45% of patients with IBD were non-adherent. Our study aimed to investigate the different aspects of adherence and to identify predictors of non-adherence, including the quality of care, for outpatients with IBD. MATERIALS AND METHODS: An anonymous electronic questionnaire was used to investigate different aspects of adherence, the quality of care, patient involvement and shared decision making among 377 IBD outpatients. RESULTS: Three hundred (80%) filled in the questionnaire. The overall adherence rate was 93%. Young age (< 35 years old) and smoking were significantly associated with non-adherence (prevalence odds ratio (POR) 2.98, 95% CI 1.04-8.52, p < 0.05 and POR 3.88, 95% CI 1.36-11.05, p < 0.05, respectively). The lowest medical adherence rates were found for 5-ASA and topical treatments among patients with inactive disease. A large majority of patients stated that treatment strategies were agreed upon as a shared decision between the patient and the health care professionals. CONCLUSIONS: Predictors for non-adherence were young age and smoking. High adherence rates could be explained by a high patient satisfaction and a high degree of shared decision making.

Self-reported adherence to medical treatment, breastfeeding behaviour, and disease activity during the postpartum period in women with Crohn's disease.

OBJECTIVES: Adherence to medical treatment among women with Crohn's disease (CD) in the postpartum period has never been examined. The impact of breast-feeding on disease activity remains controversial. We aimed to assess rates of non-adherence to medical treatment among women with CD in the postpartum period. Further, to assess breast-feeding rates and the impact of breast-feeding on the risk of relapse. METHODS: Within a population of 1.6 million, we identified 154 women with CD who had given birth within a 6-year period. We combined questionnaire data, data from medical records and public register data. We used logistic regression to estimate prevalence odds ratios (POR) for non-adherence, relapse and breast-feeding according to different predictors. RESULTS: Among 105 (80%) respondents, 59 (56%) reported taking medication. Of these, 66.1% reported to be adherent to medical treatment. Fear of medication transmission to the breast milk was stated as the reason for non-adherence in 60%. Those who received counselling regarding medical treatment were less likely to be non-adherent (POR 0.55, 95% confidence interval [CI] 0.1-2.5). In total, 87.6% were breast-feeding. Breast-feeding rates did not vary by medical treatment. Predictors for relapse in CD were smoking (POR 1.85, 95% CI 0.62-5.54) and non-adherence among medical treated (POR 1.25, 95% CI 0.26-6.00). Breast-feeding seemed protective against relapse (POR 0.33, 95% CI 0.10-1.26). CONCLUSIONS: Adherence to medical treatment in the postpartum period was high, and counselling seemed to increase adherence. Relapse may be explained by non-adherence or smoking while breast-feeding seemed protective.

Influence of medical treatment, smoking and disease activity on pregnancy outcomes in Crohn's disease.

OBJECTIVE. Little is known about predictors for adverse pregnancy outcomes among women with Crohn's disease (CD). In this population-based study, we examined pregnancy outcomes in CD stratified by medical treatment and smoking status while accounting for disease activity. METHODS. In two Danish regions with a population of 1.6 million, we identified 154 CD women who had given birth within a 6-year period. We combined questionnaire data, prescription data, data from medical records and population-based medical databases. We used logistic regression to estimate prevalence odds ratios (POR) for adverse pregnancy outcomes by different predictors. RESULTS. Among 105 (80%) respondents, 55 (52%) reported taking medication during pregnancy. The majority (95%) were in disease remission. The children's mean birth weight did not differ by maternal medical treatment. As expected, smoking was a predictor of low birth weight. Mean birth weight in children of smokers in medical treatment was significantly reduced by 274 g compared with children of non-smokers who received medical treatment. In children of women without medical treatment, this difference was 126 g between smokers and non-smokers. Women in medical treatment did not have an increased risk of preterm delivery (POR 0.71; 95% confidence interval (CI) 0.18-2.79), congenital malformations (POR 0.60; 0.10-3.76) or cesarean section (POR 1.40; 0.63-3.08). CONCLUSIon. In CD, smoking was negatively associated with child birth weight. This association was most pronounced among women who received medical treatment. Maternal medical treatment for CD did not seem to be a risk factor for adverse pregnancy outcomes.

Time to Diagnosis and Birth Outcomes of Pregnancy-onset IBD.

BACKGROUND: Pregnancy-onset inflammatory bowel disease (PO-IBD) may pose a clinical challenge. We investigated the clinical course of PO-IBD, including time to diagnosis, medical treatment, and the impact on birth outcomes. METHODS: All pregnancies in women with IBD at a tertiary IBD center in Denmark were identified from 2008 to 2021. Maternal and offspring outcome data, retrieved from medical records of women with new onset IBD during pregnancy, were compared with the outcomes of women with IBD diagnosed prior to pregnancy (controls). Outcomes included subtype of IBD, disease location, medical treatment, birth weight, intrauterine growth retardation (IUGR), gestational age at birth, caesarean section, stillbirth, congenital malformations, and time elapsed from onset of symptoms to diagnosis. RESULTS: In total, 378 women contributed with 583 pregnancies. Pregnancy-onset IBD affected 34 (9.0%) women. Ulcerative colitis (UC; n = 32) was more prevalent than Chron's disease (CD; n = 2). Birth outcomes in pregnancies affected by PO-IBD were comparable to that of the 549 controls. Women with PO-IBD received more corticosteroids and biologics following their diagnosis than did the controls (5 [14.7%] vs 2 [2.9%]; P = .07; and 14 [41.2%] vs 9 [13.2%]; P = .003, respectively). Concerning time to IBD diagnosis, there was no statistically significant difference between the 2 groups (PO-IBD, 2.5 months, interquartile range [2-6] vs controls 2 months [1-4.5]; P = .27). CONCLUSION: Although we observed a trend towards a diagnostic delay, PO-IBD was not associated with a significantly increased time to diagnosis. Birth outcomes in women with PO-IBD were comparable to those diagnosed with IBD prior to pregnancy.

Pregnancy-Onset IBD (PO-IBD) is rare and can be difficult to diagnose. The present study however reveals no significant difference in time-to-diagnosis between women with PO-IBD and women diagnosed with IBD while not pregnant.

Preterm Birth and in Utero Exposure to Corticosteroids Are Associated With Increased Infection Risk in Children of Mothers With IBD.

BACKGROUND: Corticosteroids, thiopurines, and biologics may come into play during pregnancy in women with inflammatory bowel disease and potentially impact the developing fetal immune system. We aimed to assess the risk of serious infections in children stratified by in utero exposure to biologics and immunomodulators or concomitant treatment with corticosteroids. METHODS: All singleton IBD pregnancies between 2008 and 2022 at a tertiary IBD center in Denmark were included. Maternal and offspring demographics, maternal disease activity, antenatal medical treatment, and infant infections resulting in hospital admission were recorded after review of medical records. RESULTS: In 602 live births (99.0%), we registered exposure to antenatal treatment as follows: biological monotherapy (n = 61, 10.2%), thiopurines (n = 110, 17.9%), biologics and concomitant thiopurines (n = 63, 10.3%), and controls (ie, no treatment with biological and/or thiopurines; n = 369, 60.6%). Preterm delivery (<37 gestational weeks) and systemic steroid administration during the third trimester were associated with an increased risk of serious infection in the offspring immediately after birth (relative risk = 17.5; 95% confidence interval, 7.8-39.8; P < .001, and relative risk = 4.8; 95% confidence interval, 1.5-12.7; P = 0.003, respectively).Intra-uterine exposure to biologics or combination treatment were not associated with a statistically significant higher risk of serious infections compared with controls; however, combination treatment showed an inclination towards an increased risk across analyses. CONCLUSION: Preterm birth and systemic corticosteroid administration late in pregnancy are significant risk factors for serious infections in the offspring of IBD mothers.

Preterm birth and systemic corticosteroid administration late in pregnancy are significant risk factors for serious infections in the offspring of IBD mothers.

Osmolality in oral supplements drives ileostomy output: Defining the Goldilocks zone.

BACKGROUND: Patients with an ileostomy often have impaired quality of life, sodium depletion, secondary hyperaldosteronism, and other organ-specific pathologies. The osmolality of oral supplements influences ileostomy output and increases sodium loss. We hypothesized the existence of an osmolality range in which fluid absorption and secondary natriuresis are optimal. METHODS: This was a single-center, quasi-randomized crossover intervention study, including patients with an ileostomy and no home parenteral support. After an 8-h fasting period, each patient ingested 500 mL of 3-18 different oral supplements and a standardized meal during the various intervention periods, followed by a 6-h collection of ileostomy and urine outputs. The primary outcome was 6-h ileostomy output. RESULTS: A total of 14 ileostomy patients with a median age of 65 years (interquartile range 38-70 years) were included. The association between osmolalities (range 5-1352 mOsm/kg) and ileostomy output forecasted an S-curve. A linear association between osmolality of oral supplements (range 290-600 mOsm/kg) and ileostomy output was identified and assessed with a mixed-effects model. Ileostomy output increased by 57 g/6 h (95% confidence interval (CI) 21-94) when the oral supplement osmolality increased by 100 mOsm/kg (p = 0.005). CONCLUSION: Osmolality in oral supplements correlated with ileostomy output. Our results indicate that patients with an ileostomy may benefit from increased ingestion of oral supplements with osmolalities between 100 and 290 mOsm/kg. We define this range as the Goldilocks zone, equivalent to optimal fluid and electrolyte absorption.

Reduced T2*-weighted placental MRI predicts foetal growth restriction in women with chronic rheumatic disease-a Danish explorative study.

OBJECTIVES: Women with chronic rheumatic disease (CRD) are at greater risk of foetal growth restriction than their healthy peers. T2*-weighted magnetic resonance imaging of placenta (T2*P-MRI) is superior to conventional ultrasonography in predicting birth weight and works as a proxy metabolic mirror of the placental function. We aimed to compare T2*P-MRI in pregnant women with CRD and healthy controls. In addition, we aimed to investigate the correlation between T2*P-MRI and birth weight. METHODS: Using a General Electric (GE) 1.5 Tesla, we consecutively performed T2*-weighted placental MRI in 10 women with CRD and 18 healthy controls at gestational week (GW)24 and GW32. We prospectively collected clinical parameters during pregnancy including birth outcome and placental weight. RESULTS: Women with CRD had significantly lower T2*P-MRI values at GW24 than healthy controls (median T2*(IQR) 92.1 ms (81.6; 122.4) versus 118.6 ms (105.1; 129.1), p = 0.03). T2*P-MRI values at GW24 showed a significant correlation with birth weight, as the T2*P-MRI value was reduced in all four pregnancies complicated by SGA at birth. Three out of four pregnancies complicated by SGA at birth remained undetected by routine antenatal ultrasound. CONCLUSION: This study demonstrates reduced T2*P-MRI values and a high proportion of SGA at birth in CRD pregnancies compared to controls, suggesting an increased risk of placental dysfunction in CRD pregnancies. T2*P-MRI may have the potential to focus clinical vigilance by identifying pregnancies at risk of SGA as early as GW24. Key Points • Placenta-related causes of foetal growth restriction in women with rheumatic disease remain to be investigated. • T2*P-MRI values at gestational week 24 predicted foetuses small for gestational age at birth. • T2*P-MRI may indicate pregnant women with chronic rheumatic disease (CRD) in need of treatment optimization.

Effectiveness and safety of a third-line rescue treatment for acute severe ulcerative colitis refractory to infliximab or ciclosporin (REASUC study).

BACKGROUND: The advent of new therapeutic agents and the improvement of supporting care might change the management of acute severe ulcerative colitis (ASUC) and avoid colectomy. AIMS: To evaluate the colectomy-free survival and safety of a third-line treatment in patients with ASUC refractory to intravenous steroids and who failed either infliximab or ciclosporin. METHODS: Multicentre retrospective cohort study of patients with ASUC refractory to intravenous steroids who had failed infliximab or ciclosporin and received a third-line treatment during the same hospitalisation. Patients who stopped second-line treatment due to disease activity or adverse events (AEs) were eligible. We assessed short-term colectomy-free survival by logistic regression analysis. Kaplan-Meier curves and Cox regression models were used for long-term assessment. RESULTS: Among 78 patients, 32 received infliximab and 46 ciclosporin as second-line rescue treatment. Third-line treatment was infliximab in 45 (58%), ciclosporin in 17 (22%), tofacitinib in 13 (17%) and ustekinumab in 3 (3.8%). Colectomy was performed in 29 patients (37%) during follow-up (median 21 weeks). Of the 78 patients, 32 and 18 were in clinical remission at, respectively, 12 and 52 weeks. At the last visit, 25 patients were still on third-line rescue treatment, while 12 had stopped it due to clinical remission. AEs were reported in 26 (33%) patients. Two patients died (2.6%), including one following colectomy. CONCLUSION: Third-line rescue treatment avoided colectomy in over half of the patients with ASUC and may be considered a therapeutic strategy.

Predictors of disease activity during pregnancy in women with inflammatory bowel disease-a Danish cohort study.

BACKGROUND AND AIMS: Inflammatory bowel disease (IBD) activity during pregnancy is associated with adverse pregnancy outcomes. We aimed to identify key clinical characteristics that predict disease activity during pregnancy. METHODS: Between January 2008 through 2021, we identified all singleton pregnancies among women with IBD recorded in patient and birth registries at a tertiary IBD centre in Denmark. Maternal and infant data were retrieved from medical records. Demographics, Physicians Global Assessment (PGA) of disease activity 6 months prior to pregnancy and in all three trimesters of pregnancy and pregnancy outcomes were recorded. RESULTS: In 609 pregnancies, we observed 603 (99.0%) live births. Disease activity in one or more trimesters was seen in 283 women (46.5%). UC phenotype was associated with an increase in risk of disease activity (adjusted OR = 2.6 [1.8-3.9]; p < 0.001). Disease activity within 6 months prior to conceiving (169 women [27.7%]) was associated with an increased risk of continuous disease activity during pregnancy (adjusted OR of 5.3 [3.5-8.2]; p < 0.001). Disease activity during a previous pregnancy was associated with an increased risk of flares in subsequent pregnancies (adjusted OR of 3.2 [1.5-6.6]; p = 0.002). Sustained clinical remission throughout pregnancy was associated with an increased probability of normal birth term, birthweight and low risk of fetal growth restriction (FGR) and stillbirth. CONCLUSION: Predictors for disease activity include disease activity in a previous pregnancy and/or prior to conception, as well as UC phenotype. Reassuringly, women with IBD in remission are not at increased risk of adverse pregnancy outcomes.

Validation of the pharmacokinetic model for anti- TNFα clearance in infants exposed to anti- TNFα during pregnancy.

BACKGROUND AND AIMS: ECCO guideline recommend postponing live attenuated vaccines in infants exposed to anti-Tumor Necrosis Factor alpha (anti-TNFα) in utero until drug clearance. The aim was to validate the predictive performance of the anti-TNFα clearance model. METHODS: Newborns and anti-TNFα concentrations from the prospective PETIT cohort were included. The anti-TNFα clearance model was used to predict all measured concentrations in the PETIT cohort, based on the measured cord blood concentration and the mean population clearance described in the model. Bayesian maximum a posteriori optimization was used to estimate the value of drug monitoring. Predictive capability and drug monitoring were assessed through Mean Absolute Error (MAE), Root mean Squared Prediction Error and Limits of Agreement according to Bland and Altman. RESULTS: Observed drug concentrations after birth were within the 80% prediction interval in 94% of adalimumab samples and 93% of infliximab samples. The anti-TNFα clearance model accurately predicted the concentration at six months after birth with an MAE of 0.03 (SD 0.03) µg/mL for adalimumab and 0.11 (SD 0.18) µg/mL for infliximab based on cord blood concentrations. Addition of an additional sample between 1 and 4 months after birth improved the predictive accuracy for infliximab (MAE 0.05 (SD 0.09)) but not for adalimumab. Guidance for use in clinical practice was formulated. CONCLUSIONS: The validity of the anti-TNFα clearance model is high, and hence can be used to guide clinicians regarding timing of live vaccines in infants exposed to adalimumab or infliximab in utero.

Non-hepatic Solid Organ Transplant in Patients with Inflammatory Bowel Disease: An ECCO CONFER Multicentre Case Series.

BACKGROUND AND AIMS: Solid organ transplantation, with the exception of liver, has rarely been reported in patients affected by inflammatory bowel diseases [IBD]. METHODS: This is an ECCO-CONFER project collecting cases of solid organ transplants [with the exclusion of liver] that were performed in IBD patients. We evaluated the change in the IBD therapy, need for bowel resection due to medically refractory IBD, or need for hospitalisation due to IBD relapse ['severe IBD course'] before and after transplantation. RESULTS: in total, 34 organ transplantations [28 kidney, five heart, one lung] in 33 IBD patients were collected [67% male, 55% Crohn's disease, mean age 53 ±â€…16 years]. The median follow-up was 4.3 years (interquartile range [IQR] 3.2-10.7); 29 patients [87.9%] were treated with tacrolimus, 25 [76%] with systemic steroids, 22 [67%] with mycophenolate mofetil, 11 [33%] with everolimus, six with cyclosporine [18%]. One patient was treated with infliximab, two patients with adalimumab, two patients with vedolizumab, one patient with ustekinumab. Overall, a severe IBD course was observed in three [9.3%] patients before transplantation and in four [11.7%] in the post-transplant setting [p = 0.26]. Three cases of cancer [excluding skin non-melanoma] [9.1%] were recorded in the post-transplantation period versus two in the pre-transplantation period [6.1%, p = 0.04]. Six patients [18.2%] died during the period of observation. No deaths were associated with IBD or complications of the transplant. CONCLUSIONS: In IBD patients, solid organ transplantation does not seem to impact on the IBD severity. However, the risk of malignancy needs further investigation.

A Core Outcome Set for inflammatory bowel diseases: development and recommendations for implementation in clinical practice through an international multi-stakeholder consensus process.

BACKGROUND AND AIMS: Standardising health outcome measurements supports delivery of care, enables data-driven learning systems, and secondary data use for research. As part of the Health Outcomes Observatory initiative and building on existing knowledge, a core outcome set (COS) for inflammatory bowel diseases (IBD) was defined through an international modified Delphi method. METHODS: Stakeholders rated 90 variables on a 9-point importance scale twice, allowing score modification based on feedback displayed per stakeholder group. Two consecutive consensus meetings were held to discuss results and formulate recommendations for measurement in clinical practice. Variables scoring 7 or higher by ≥80% of the participants, or based on consensus meeting agreement, were included in the final set. RESULTS: In total, 136 stakeholders (45 IBD patients (advocates), 74 healthcare professionals/researchers, 13 industry representatives and 4 regulators), from 20 different countries participated. The final set includes 18 case-mix variables, 3 biomarkers (haemoglobin to detect anaemia, C-reactive protein and faecal calprotectin to detect inflammation) for completeness and 28 outcomes (including 16 patient-reported outcomes (PROs) and 1 patient-reported experience). The PRO-2 and IBD-Control questionnaires were recommended to collect disease-specific PROs at every contact with an IBD practitioner, and the Subjective Health Experience model questionnaire, PROMIS Global Health and Self-Efficacy short form to collect generic PROs annually. CONCLUSIONS: A COS for IBD, including a recommendation for use in clinical practice, was defined. Implementation of this set will start in Vienna, Berlin, Barcelona, Leuven and Rotterdam, empowering patients to better manage their care. Additional centres will follow worldwide.

Timing of Live Attenuated Vaccination in Infants Exposed to Infliximab or Adalimumab in Utero: A Prospective Cohort Study in 107 Children.

BACKGROUND AND AIMS: For infants exposed in utero to anti-tumour necrosis factor-α [TNF] medications, it is advised that live-attenuated vaccinations be postponed until the drug is cleared, but little is known about time to clearance. To minimize delays before live-attenuated vaccination can be given, we aimed to develop a pharmacokinetic model to predict time-to-clearance in infants exposed during pregnancy. METHODS: We prospectively followed in utero infliximab/adalimumab-exposed infants of mothers with inflammatory bowel disease across four countries between 2011 and 2018. Infants with a detectable anti-TNF umbilical-cord level and at least one other blood sample during the first year of life were included. RESULTS: Overall, 107 infants were enrolled, including 166 blood samples from 71 infliximab-exposed infants and 77 samples from 36 adalimumab-exposed infants. Anti-TNF was detectable in 23% [n = 25] of infants at 6 months. At 12 months, adalimumab was not detected but 4% [n = 3] had detectable infliximab. A Bayesian forecasting method was developed using a one-compartment pharmacokinetic model. Model validation showed that the predicted clearing time was in accordance with the measured observations. A clinician-friendly online calculator was developed for calculating full anti-TNF clearing time: https://xiaozhu.shinyapps.io/antiTNFcalculator2/. CONCLUSIONS: Almost one-quarter of infants born to mothers receiving anti-TNF during pregnancy have detectable anti-TNF at 6 months. To limit the time to live-attenuated vaccination in infants of mothers receiving anti-TNF during pregnancy, the results of a cord drug level at birth and a second sample ≥ 1 month thereafter can be used to estimate the time for full anti-TNF clearance in these children.